RESUMEN
This study aimed to investigate the biofilm-production ability of carbapenem-resistant Acinetobacter baumannii (CRAB), the biofilm-eradication potential of 70% ethanol and 0.5% sodium hypochlorite, the effects of selenium nanoparticles (SeNPs) against planktonic and biofilm-embedded CRAB, and the relationship between biofilm production and bacterial genotypes. A total of 111 CRAB isolates were tested for antimicrobial susceptibility, biofilm formation, presence of the genes encoding carbapenemases, and biofilm-associated virulence factors. The antibiofilm effects of disinfectants and SeNPs against CRAB isolates were also tested. The vast majority of the tested isolates were biofilm producers (91.9%). The bap, ompA, and csuE genes were found in 57%, 70%, and 76% of the CRAB isolates, with the csuE being significantly more common among biofilm producers (78.6%) compared to non-biofilm-producing CRAB (25%). The tested disinfectants showed a better antibiofilm effect on moderate and strong biofilm producers than on weak producers (p < 0.01). The SeNPs showed an inhibitory effect against all tested planktonic (MIC range: 0.00015 to >1.25 mg/mL) and biofilm-embedded CRAB, with a minimum biofilm inhibitory concentration of less than 0.15 mg/mL for 90% of biofilm producers. In conclusion, SeNPs might be used as promising therapeutic and medical device coating agents, thus serving as an alternative approach for the prevention of biofilm-related infections.
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Group B Streptococcus (GBS) is a major cause of neonatal morbidity and mortality. Serbia has not fully implemented preventive measures against GBS neonatal diseases. Therefore, we aimed to assess the maternal GBS colonisation and invasive neonatal disease rate, to reveal the trends of antimicrobial resistance and serotype distribution of GBS from various patient groups. Randomly selected non-invasive (n = 991) and all invasive GBS (n = 80) collected throughout Serbia from 2015 to 2020 were tested for antimicrobial susceptibility, capsular typing, and hvgA detection. Overall, 877/5621 (15.6%) pregnant women were colonised with GBS. Invasive GBS infections incidence in infants (0.18/1000 live births) showed a decreasing trend (0.3 to 0.1/1000 live births). Type III was overrepresented in infants with invasive infections (n = 35, 58.3%), whereas type V predominated among colonised adults (n = 224, 25.5%) and those with noninvasive (n = 37, 32.5%) and invasive infections (n = 8, 40%). The hypervirulent clone III/ST17 was highly associated with invasive infections (n = 28, 35%), particularly late-onset disease (n = 9, 47.4%), showing an increase from 12.3 to 14.8%. The GBS resistance to erythromycin and clindamycin was 26.7% and 22.1%, respectively, with an upward trend. The emergence of the hypervirulent clone III/ST17 and the escalation in GBS resistance highlight an urgent need for continuous monitoring of GBS infections.
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Antibacterianos/farmacología , Enfermedades del Recién Nacido/microbiología , Infecciones Estreptocócicas/microbiología , Streptococcus agalactiae/efectos de los fármacos , Clindamicina/farmacología , Farmacorresistencia Bacteriana/genética , Eritromicina/farmacología , Femenino , Humanos , Recién Nacido , Enfermedades del Recién Nacido/epidemiología , Masculino , Embarazo , Complicaciones Infecciosas del Embarazo/epidemiología , Complicaciones Infecciosas del Embarazo/microbiología , Prevalencia , Serbia/epidemiología , Infecciones Estreptocócicas/epidemiología , Streptococcus agalactiae/genética , Streptococcus agalactiae/patogenicidad , Factores de TiempoRESUMEN
The potential problems of DNA extraction from formalin-fixed paraffin-embedded (FFPE) tissue samples and amplification efficiency of Human papilloma virus (HPV) may occur in the molecular studies of head and neck squamous carcinoma (HNSCC). The aim of this study was to compare HPV detection rate in FFPE tissues of oral, oropharyngeal, hypopharyngeal, and laryngeal cancers using two silica-based extraction kits and three amplification methods. A total of 50 FFPE specimens from HNSCC tissues were analyzed. The quality and quantity of the extracted DNA were tested by spectrophotometry. HPV DNA was detected using a single polymerase chain reaction (PCR), a nested PCR, and a Real-time PCR kit. Statistically significantly higher DNA quality and quantity was observed using the QIAamp DNA FFPE Tissue Kit than when using the QIAamp DNA Mini Kit. There was not HPV amplification in any of the 50 FFPE samples using the single PCR and Real-time PCR kits, whereas HPV DNA was detected in 22% of samples using nested PCR. Comparing results of the three different methods showed that HPV DNA was detected only with nested PCR. The results presented imply that nested PCR is the most appropriate method for the detection of HPV DNA in FFPE samples, along with adequate DNA extraction methods.
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Alphapapillomavirus , Carcinoma , Papillomaviridae , Infecciones por Papillomavirus , Alphapapillomavirus/genética , ADN , Formaldehído , Humanos , Papillomaviridae/genética , Infecciones por Papillomavirus/diagnóstico , Adhesión en Parafina , Fijación del TejidoRESUMEN
Due to its ubiquity, ability to form biofilms, and acquire resistance mechanisms, Pseudomonas spp. become one of the major challenge for healthcare settings and food industry. The aims of this study were to assess the biofilm production of Pseudomonas spp. recovered from clinical and food specimens and to evaluate their antimicrobial resistance. A total of 108 isolates of Pseudomonas spp. were included in the study, 48 being clinical isolates recovered from patients admitted to four tertiary care hospitals throughout Serbia and 60 were isolated from the bulk tank milk samples and meat carcasses. Biofilm production was analyzed by microtiter plate assay. Antimicrobial susceptibility was evaluated by disk diffusion method according to the CLSI guidelines, while class A and B ß-lactamases encoding genes were screened by PCR. A total of 98 (90.7%) strains were biofilm producers (moderate producer: 68, 69.4%; strong producer: 8, 8.2%). Although a slightly higher percentage of clinical isolates were biofilm producers (91.7%) compared to food isolates (90%), statistical significance was not observed (P > 0.05). The proportion of carbapenem-resistant Pseudomonas aeruginosa (CRPA) isolates was significantly higher among clinical (42%) isolates compared to food (1.7%) Pseudomonads (P < 0.05). The blaPER and blaNDM genes were found in ESBL (seven isolates) and MBL (two isolates) production, respectively. In the present study, we confirmed that biofilm formation was highly present in both clinical and food Pseudomonas spp. irrespective of the prior existence of resistance genes. Additionally, clinical settings pose a major reservoir of MDR Pseudomonas spp. and especially CRPA isolates.
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Antibacterianos , Farmacorresistencia Bacteriana , Infecciones por Pseudomonas , Pseudomonas/efectos de los fármacos , Antibacterianos/farmacología , Biopelículas , Microbiología de Alimentos , Humanos , Pruebas de Sensibilidad Microbiana , Pseudomonas/genética , Pseudomonas aeruginosa/efectos de los fármacos , Pseudomonas aeruginosa/genética , beta-LactamasasRESUMEN
Tigecycline can be effective to treat infections of carbapenem-resistant Acinetobacter baumannii (CRAB) however, no interpretive criteria have been approved so far. The objectives of this study were to evaluate the proportion of CRAB isolates and to compare gradient test with a broth microdilution (BMD) method for tigecycline susceptibility testing of A. baumannii.This study included 349 multidrug-resistant (MDR) Acinetobacter spp. collected from Serbia, Montenegro, Bosnia and Herzegovina in 2016 and 2017. Antibiotic susceptibility testing was performed by disk diffusion, VITEK2, gradient, ComASP Colistin. Tigecycline susceptibilities were interpreted according to breakpoints of European Committee on Antimicrobial Susceptibility Testing (EUCAST) and Food and Drug Administration (FDA).Majority of the tested isolates were CRAB (92.8%). Tigecycline MIC50/MIC90 values were 4/8 µg/mL by BMD and 0.5/4 µg/mL by gradient test. Essential agreement for BMD and gradient test amounted to 65.1%. With EUCAST breakpoints, categorical agreement (CA) was achieved in 38% isolates. Major discordance (MD-false susceptibility/resistance) and minor discordance (mD-false categorization involving intermediate results) were observed in 10% and 57% A. baumannii, respectively. With FDA breakpoints, CA, MD and mD were observed in 44%, 16% and 47% isolates, respectively. Colistin resistance was 2.1%.The study highlights a high proportion of CRAB and several discordances between BMD and gradient test which may lead to inappropriate therapy.
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Infecciones por Acinetobacter/epidemiología , Infecciones por Acinetobacter/microbiología , Acinetobacter baumannii/efectos de los fármacos , Antibacterianos/farmacología , Farmacorresistencia Bacteriana Múltiple , Tigeciclina/farmacología , Acinetobacter baumannii/aislamiento & purificación , Peninsula Balcánica/epidemiología , Carbapenémicos/farmacología , Hospitalización , Humanos , Unidades de Cuidados Intensivos , Pruebas de Sensibilidad MicrobianaRESUMEN
Numerous reports have confirmed that increased macrolide use in the treatment of respiratory tract infection has contributed to the emergence of antibiotic resistance worldwide. Studies have also shown that pneumococcal vaccine can reduce pneumococcal resistance. The aim of this study was to determine the prevalence of co-resistance to penicillin and other antibiotics in macrolide-resistant (MR) non-invasive pneumococcal isolates and to evaluate serotype distribution in resistant strains in the pre-vaccine era in Serbia. About 80% of MR isolates expressed the MLS phenotype with very high resistance to both erythromycin and clindamycin. A total of 132 (84.1%) MR isolates were multiresistant, i.e., they were resistant to erythromycin, penicillin, tetracycline, and trimethoprim-sulfamethoxazole. Among 157 MR pneumococci, 11 different serotypes were found. Four serotypes, 19F, 14, 6B, and 23F, accounted for 77.7% of all MR pneumococcal isolates. Among isolates with the cMLS phenotype, serotypes 19F and 14 were predominant, whereas serotype 6A was the most common among those with the M phenotype, followed by 14. In conclusion, co-resistance to macrolides and penicillin in our non-invasive pneumococcal isolates is high. The majority of tested strains (â¼80%) belonged to the four serotypes (19F, 14, 6B, and 23F) that are included in all conjugate vaccine formulations.
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Antibacterianos/farmacología , Farmacorresistencia Bacteriana , Macrólidos/farmacología , Infecciones Neumocócicas/epidemiología , Infecciones Neumocócicas/microbiología , Streptococcus pneumoniae/efectos de los fármacos , Streptococcus pneumoniae/aislamiento & purificación , Pruebas de Sensibilidad Microbiana , Fenotipo , Prevalencia , Serbia/epidemiología , Serogrupo , Serotipificación , Streptococcus pneumoniae/clasificaciónRESUMEN
In this study, the focus was on the effects of sub-MICs of the antibiotics on adherence, hydrophobicity, and biofilm formation by two groups of Streptococcus pyogenes strains, which were responsible for different clinical cases. The aim of this study was to explore the effects of sub-MICs of penicillin, ceftriaxone, erythromycin, and clindamycin on adherence, surface hydrophobicity, and biofilm biomass in two selected collections of group A streptococcus (GAS): strains isolated from carriers (CA) and strains isolated from patients with tonsillopharyngitis (TPh). Isolates were tested for hydrophobicity to xylene, adherence, and biofilm production in uncoated microtiter plates before and after treatment with 1/2 and 1/4 MICs of antibiotics. Penicillin reduced adherence and biofilm production in TPh strains, whereas ceftriaxone diminished adherence and biofilm formation in CA group. On the contrary, clindamycin enhanced adherence and biofilm production in both groups of strains. Erythromycin did not significantly alter adherence, but triggered biofilm production in both groups of isolates. Hydrophobicity of both groups of strains was significantly reduced after exposure to all antibiotics. Beta-lactams displayed anti-biofilm activity; penicillin diminished both adherence and biofilm production in TPh strains, whereas ceftriaxone reduced it in strains isolated from CA.
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Antibacterianos/farmacología , Adhesión Bacteriana/efectos de los fármacos , Biopelículas/crecimiento & desarrollo , Streptococcus pyogenes/efectos de los fármacos , Antibacterianos/administración & dosificación , Pruebas de Sensibilidad Microbiana , Streptococcus pyogenes/fisiologíaRESUMEN
In Serbia, the frequency of macrolide-resistant group A streptococci (MRGASs) increased significantly from 2006 to 2009. MRGAS analysis in 2008 revealed the presence of three major clonal lineages: emm75/mefA, emm12/mefA, and emm77/ermTR. The aim of the present study was to determine the prevalence of macrolide resistance and to evaluate variations in the clonal composition of MRGASs. The study included 1,040 pharyngeal group A streptococci collected throughout Serbia, which were tested for antimicrobial susceptibility. MRGAS isolates were further characterized by the presence of resistance determinants, emm typing, and pulsed-field gel electrophoresis analysis. The prevalence of macrolide resistance was 9.6%, showing a slight decrease compared with the rate of 12.5% (2008). Tetracycline resistance was present in 6% of isolates, while norfloxacin nonsusceptibility detected for the first time in Serbia was 9.8%. The M phenotype dominated (84%), followed by the constitutive macrolides, lincosamides, and streptogramin B phenotype (12%). Five emm types were detected: emm75, emm12, emm1, emm28, and emm89. The emm75/mefA (62%), emm12/mefA (14%), and emm12/ermB/tetM (6%) were predominant clones and were found in both the present and the previous study periods at different frequencies. The major change was the loss of emm77/ermTR/tetO, which contributed to 15% of MRGASs in 2008.
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Farmacorresistencia Bacteriana/genética , Macrólidos/farmacología , Streptococcus/efectos de los fármacos , Streptococcus/genética , Adolescente , Antibacterianos/farmacología , Niño , Preescolar , Evolución Clonal , Farmacorresistencia Bacteriana/efectos de los fármacos , Femenino , Genes Bacterianos/genética , Genotipo , Humanos , Lincosamidas/farmacología , Masculino , Pruebas de Sensibilidad Microbiana/métodos , Fenotipo , Serbia , Infecciones Estreptocócicas/tratamiento farmacológico , Infecciones Estreptocócicas/microbiología , Tetraciclina/farmacologíaRESUMEN
This study investigated the possible relationship between the invasiveness of group A Streptococcus (GAS) strains and their abilities to adhere to laminin and assessed the effects of subinhibitory concentrations of penicillin and erythromycin on the ability of GAS to adhere to laminin. The adherence of noninvasive and highly invasive isolates of GAS to laminin was significantly higher than the adherence displayed by isolates of low invasiveness. Antibiotic treatment caused significant reductions in adherence to laminin in all three groups of strains. Penicillin was more successful in reducing the adherence abilities of the tested GAS strains than erythromycin.
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Antibacterianos/farmacología , Adhesión Bacteriana/efectos de los fármacos , Eritromicina/farmacología , Laminina/efectos de los fármacos , Penicilinas/farmacología , Streptococcus pyogenes/efectos de los fármacos , Humanos , Pruebas de Sensibilidad MicrobianaRESUMEN
INTRODUCTION: Escherichia coli (E. coli) are the most frequent cause of the urinary tract infections. Uropathogenic E. coli (UPEC) produce virulence factors which enable them to survive in the urinary tract and cause an infection. OBJECTIVE: The objective of this study was to determine phenotype characterization of E. coli isolated from outpatients' urine in the region of Banja Luka over three-year period. In line with the objective, the following research tasks were set up: determining the production of type 1 fimbriae, P-pili, alpha-hemolysin and siderophores. METHODS: A total of 417 urinary isolates and 100 control intestinal isolates were screened for virulence factors. Production of adhesions was confirmed by haemagglutination test. Plate haemolysis test was done for the detection of alpha-hemolysin, and siderophores production assay was carried out by using the method named chrome azurol sulfonate agar diffusion assay. RESULTS: In the group of urinary isolates, almost 60% of isolates produced two or three virulence factors; only 3.8% produced none of the virulence factors. In the group of intestinal isolates, even 43% of isolates produced none of the virulence factors while 48% of isolates produced a single virulence factor and 9% produced two virulence factors. CONCLUSION: Urinary isolates E. coli express significantly more P-pili, alpha-hemolysin and siderophore than intestinal isolates (p < 0.001).There was no significant difference in production of type 1 fimbriae among the urinary and intestinal isolates.
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Infecciones por Escherichia coli/orina , Proteínas Fimbrias/orina , Fimbrias Bacterianas , Proteínas Hemolisinas/orina , Sideróforos/orina , Infecciones Urinarias/orina , Escherichia coli , HumanosRESUMEN
INTRODUCTION: In Gram-negative bacteria, the production of beta-lactamases is the most important mechanism of resistance to beta-lactam antibiotics. In the Banja Luka region, there were no extensive researches on the prevalence and antimicrobial resistance of the extended-spectrum beta-lactamase (ESBL) producing Escherichia coli (E. coli) isolates. OBJECTIVE: The aim of the present study was to determine the presence of ESBL producing E. coli isolates as the cause of the urinary tract infections in outpatients, the distribution of these ESBL isolates according to age and gender of patients and their susceptibility to antimicrobials. METHODS: Urine specimens obtained from outpatients were cultured on chromogenic CPS-ID3 media. All plates showing significant (> 10(5) cfu/ml) growth of E. coli in pure culture were further processed. Antimicrobial susceptibility testing was performed on VITEK TWO Compact using AST-GN27 cards for testing Gram negative bacteria and detection of ESBL producers. RESULTS: Out of 2,195 isolates, 177 (8.1%) were ESBL producers. Ninety-two isolates were obtained from female patients (5% of E. coli isolated from women) and 85 isolates from male patients (23% of E. coli isolated from men). High percentage of ESBL isolates was detected in the infant age group under one year (36.7%) and in the age group over 60 years (28.8%). All ESBL isolates were susceptible to imipenem and resistant to ampicillin, piperacillin, cefazolin, cefotaxime, ceftazidime and cefepime. There was a significant resistance to amikacin (79.1%), gentamicin (76.8%), amoxicillin/clavulanate (54.8%) and trimethoprim/sulphamethoxazole (45.8%). Resistance to nutrofurantoin was 13.6%. CONCLUSION: This study has demonstrated the presence of ESBL producing E. coli urinary isolates in outpatients, and their extensive susceptibility to imipenem and nitrofurantoin.