Healthcare workers may pave the way for increased infections in hospitalized patients by coagulase-negative staphylococci (CoNS). Biofilm formation and antibiotic resistance are the major problems ...posed by CoNS in nosocomial infections. In this study, we determined biofilm production level and the distribution of biofilm-associated and virulence genes, including icaADBC, aap, bhp, atlE, embp, and fbe, as well as IS256, IS257, mecA, and ACME clusters (arc-A, opp-3AB) among 114 clinical (n = 57) and healthcare workers (n = 57) CoNS isolates in Kerman, Iran. In this study, more than 80% (n = 96) of isolates were methicillin-resistant CoNS (MR-CoNS). Out of 114 isolates, 33% (n = 38) were strong biofilm producers. Strong biofilm formation was found to be significantly different between clinical and healthcare workers' isolates (P < 0.050). In addition, 28% (n = 32) of isolates were positive for icaADBC simultaneously, and all were strong biofilm producers. The prevalence of icaADBC, mecA, bhp, fbe, and IS256 in clinical isolates was higher than that in healthcare workers' isolates (P < 0.050). A significant relationship was observed between clinical isolates and the presence of icaADBC, mecA, bhp, and IS256. Although these elements were detected in healthcare workers' isolates, they were more frequent in clinical isolates compared to those of healthcare workers. The high prevalence of ACME clusters in healthcare workers' isolates and biofilm formation of these isolates partially confirms the bacterial colonization in the skin of healthcare workers. Isolating MR-CoNS from healthcare workers' skin through similar genetic elements to clinical isolates, such as icaADBC, mecA, and IS256, calls for appropriate strategies to control and prevent hospital infections.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Multidrug-resistant (MDR) Escherichia coli, a species that is a leading cause of urinary tract infections (UTIs) and is a major global public health concern. This study was designed to detect the ...differences in antibiotic resistance patterns, the production and type of extended spectrum β-lactamases (ESBLs), and the clonal relationships among E. coli isolates from UTIs and fecal samples.
Antibacterial resistance was determined by the disk diffusion method. ESBL, carbapenemase, and AmpC-producing isolates were detected phenotypically. Then, the ESBL genes were sequenced to detect the type. Enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) was performed on the ESBL-positive isolates.
The most common effective antibacterial agents were colistin, imipenem, and amikacin. Among the isolates, 204 (56.6%) were MDR. Of the 163 ESBL-positive isolates, 11 (6.7%) produced AmpC, and the frequencies of beta-lactamase-positive genes were as follows: bla CTX-Mgroup1, 76%; bla TEM1, 74.8%; bla SHV12, 1.2%; and bla OXA1, 12.88%. ERIC PCR showed a diverse pattern, suggesting that clonal spread of E. coli in this area is uncommon, and that most of the infecting strains are endogenous.
The high rates of antibacterial-resistant and MDR isolates are quite important since these strains can act as source of resistant bacteria that can be spread in the community. Controlling antibiotic use, against inappropriate use and abuse, in the community and continuous surveillance of emerging resistance traits are critical to controlling the spread of resistance.
Resistance‐nodulation‐division efflux system (RND) adeABC contributes to intrinsic resistance to various drug classes in Acinetobacter baumannii. Similarly, quorum sensing (QS) plays an important ...role in the biofilm formation and pathogenicity of this bacterium. The aims of this study were to evaluate the influence of iron limitation on the expression of efflux pump (adeABC) genes and QS (luxI, luxR) system by relative quantitative real‐time polymerase chain reaction (qRT‐PCR). In addition, DNA sequence and phylogenetic relatedness of biofilm‐associated protein (Bap) gene was also investigated. Sixty‐five multidrug‐resistant isolates of A. baumannii were recovered from ICU patients of three hospitals in Kerman, Iran. The isolates were highly resistant to at least 11 antibiotics (MIC ≥64 μg/mL); however, 87% and 89% were susceptible to colistin and tigecycline, respectively (MIC 0.05 μg/mL) (p ≤ 0.05). We detected the presence of RND efflux pump, QS, and bap genes with the frequencies of 92% (adeA), 61.5% (adeB), 84.6% (adeC), 80% (luxI), 61% (luxR), and 66% (bap), respectively. qRT‐PCR analysis showed that in some isolates, expression of both adeABC and luxI/R was increased more than fourfold in the presence of low iron (20 μm), suggesting the additional regulatory role of iron on both efflux pump and QS system. Alignment and phylogenetic analysis on the strong biofilm forming isolates confirmed that the fragments amplified were indeed part of bap gene and deduced sequence was similar to A. baumannii K9B410.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
is one of the most important nosocomial pathogens causing a high rate of mortality among hospitalized patients. Herein, we report the prevalence of antibiotic resistance genes, class 1 integrons, ...major virulence genes and clonal relationship among multidrug- resistant (MDR)
, isolated from four referral hospitals in the southeast of Iran.
In this study, 208 isolates of
were collected from four referral hospitals in southeast of Iran. Disk diffusion method was used to determine susceptibility to 13 antibacterial agents. AmpC was detected by phenotypic method and β-lactamase genes, virulence genes and class 1 integrons were detected by PCR. Clonal relationship of the isolates was determined by RAPD-PCR.
All the isolates were susceptible to polymyxin-B and colistin. Overall, 40.4% of the isolates were MDR, among which resistance to third generation cephalosporins, aminoglycosides, and carbapenems was 47.5%, 32.3% and 40%, respectively. None of the isolates was positive for
genes, while 84.5% and 4.8% were positive for the
and
, metallo-β-lactamase genes, respectively. Incidence of class 1 integrons was 95% and AmpC was detected in 33% of the isolates. Prevalence of
and
were 98.8%, 44%, 26%, 8.3% and 33.3%, respectively. RAPD profiles identified four large clusters consisting of 77 isolates, and two small clusters and three singletons.
The rate of MDR
isolates was high in different hospitals in this region. High genetic similarity among MDR isolates suggests cross-acquisition of infection in the region.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Pseudomonas aeruginosa (P. aeruginosa) is a common bacteria associated with burn infections and resistance to a wide range of disinfectants and antimicrobial agents which is able to produce different ...virulence factors. In this study, the susceptibility of P. aeruginosa isolates from the burn (burn=57) and hospital environment (HE=19) to antimicrobial agents and chemical disinfectants was determined by disc and well diffusion agar method, respectively. The results showed 100% sensitivity to polymyxin B, while sensitivity to other agents was low and ranged from 40.8% for imipenem and amikacin to 6.6% for ceftizoxime. Among the disinfectant used, the mean diameter of inhibition zones (DIZ) was higher for Deconex, while nitrofurazone had the lowest DIZ. In most cases, the HE isolates were significantly more susceptible to disinfectants and antimicrobial agents compared to burn isolates (P≤0.01). The genes for the exoenzyme T, Y, U, and S were detected in 100%, 89.8%, 43.4%, and 48.7% of the isolates, respectively. The prevalence of exo U and exoY was significantly higher in the burn isolates compared to HE isolates (P=0.001). The results of this study indicate a significantly higher level of resistance against the majority of the antimicrobial agents in the burn isolates compared to HE isolates, which was significantly higher than the environmental isolates. The prevalence of T3SS effectors proteins and their pattern were also different in the burn, and the HE isolates, indicating a divergence in pathogenicity of the burn isolates from those of the environmental isolates.
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A series of N-5-(5-nitro-2-thienyl)-1,3,4-thiadiazole-2-ylpiperazinyl quinolones (7a–c) were synthesized and evaluated for in vitro antibacterial activity against some Gram-positive and Gram-negative ...bacteria. The antibacterial data revealed that compounds 7a–c had strong and better activity against tested Gram-positive organisms than the reference quinolones such as ciprofloxacin, norfloxacin and enoxacin. However, all three compounds were nearly inactive against Gram-negative bacteria. Compound 7a (ciprofloxacin analogue) was the most active compound against Gram-positive bacteria (MIC=0.008–0.015 μg mL−1).
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
This study was designed to evaluate the activity of
galls extract (QIFGE) on virulence factor production and inhibition of quorum sensing (QS) in
Minimum inhibitory concentration (MIC) of QIFGE ...against 5 strains of
was determined. The extract at sub-MIC was used to determine biofilm formation, level of protease LasA, LasB, swarming and twitching motility and QS using
CV026 as a biosensor. Effect of the extract on expression levels of
gene was determined by real time PCR.
QIFGE inhibited the QS and all other tested virulence factors compared with the control grown in the absence of the extract (P=0.001). Real time PCR showed 2 to 8-fold reduction in
gene expression in presence of the extracts compared with the control. QIFGE significantly inhibited the virulence factor production, had inhibitory effect on QS, and resulted in the lower expression of
gene.
QIFGE showed novel inhibitory effect against QS related virulence factor production, which was unrelated to antimicrobial effect. The extract can down regulate the production of virulence factor and should be evaluated as a candidate for alternative treatment of pseudomonad infections in future.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Enterococcus faecalis is an opportunistic pathogen that causes most of the enterococcal infections. Among the different factors implicated in the pathogenesis of these organisms, biofilm formation ...and antibiotic resistance are the most important. The ability for biofilm formation has been attributed to the presence of some virulence genes. However, no definite correlation has been found. This study aimed to detect biofilm formation and antibiotic resistance patterns in E. faecalis isolates collected from clinical and fecal samples, and to investigate possible correlation between some virulence genes (esp, cyl, gelE) and biofilm formation.
A collection of 123 E. faecalis isolates were investigated for antibiotic resistance and production of hemolysin, gelatinase, and biofilm using phenotypic methods. The esp, gelE and cyl genes were detected using polymerase chain reaction.
Thirty-eight pathogenic isolates (37%) were positive for biofilm formation. Additionally, the gelE, esp, and cyl genes were detected in 74 (71.8%), 79 (76.7%) and 42 (40.8%) isolates, respectively. In the fecal samples, 18 (90%) isolates were biofilm producers and 11 (55%), 17 (85%) and 8 (40%) isolates were positive for gelE, esp, and cyl, respectively. There were significant differences in biofilm production between pathogenic and fecal isolates (P <0.001). Multidrug resistance (MDR) was found among 32% (n = 33) and 15% (n = 3) of the clinical and fecal isolates, respectively. However, no significant difference was seen between MDR and biofilm formation. Five pathogenic and two fecal isolates were negative for all investigated genes while they were they were biofilm producers. In contrast, 22 pathogenic isolates and 1 fecal isolate were positive for the tested genes, but did not form any biofilm. No significant differences were observed between biofilm formation and the presence of the esp, gelE and cyl genes in the pathogenic and fecal isolates (P >0.05).
The presence of the esp, gelE and cyl genes might not be determining factors for biofilm formation in enterococci and other mechanisms might be involved in this process.
Objective(s): Escherichia coli is one of the most important causes of urinary tract infections (UTIs). The aim of this study was to determine antimicrobial resistance, resistance and virulence genes; ...phylogenetic groups and identify the epidemiologic features of uropathogenic E. coli (UPEC) isolates by multilocus sequence typing (MLST). Materials and Methods: One hundred isolates of E. coli from inpatients with UTIs were collected in Kerman, Iran. Antimicrobial susceptibility testing, ESBLs, AmpC production and biofilm formation were performed by phenotypic methods. Phylogenetic groups, resistance and virulence genes were detected. Molecular typing of isolates was performed by MLST. Results: In this study, 76% of isolates were multidrug-resistant. The blaCTX-M-15 and blaTEM were the dominant ESBL-encoding gene. Among 63 ciprofloxacin-resistant isolates, the frequency of qnrS (15.8%), qnrB (9.5%), and aac (6’)-Ib (25% ) genes was shown. Fifty-five present of isolates were classified as week biofilm, (14%) moderate biofilm, and (5%) strong. The predominant phylogenetic group was B2 (3) . The prevalence of virulence genes ranged fimH (93%), iutA (66%), KpsmtII (59%), sat (39%), cnf (28%) and hlyA (27%). According to MLST results, 14 sequence types (ST) including ST-693, ST-90, ST-101, ST-1664, ST-2083, ST-131, ST-4443, ST-744, ST-361, ST-405, ST-922, ST-648, ST-5717and ST-410 were detected, indicating a high degree of genotypic diversity. Conclusion: We identified a high frequency of the ST131 clonal group among UTIs. These data show an important public health threat, and so further studies to control the dissemination and risk factors for acquisition of the ST131 clonal group and other STs are needed to make effective control.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Antibiotics prescribed for infections have diverse effects on microbiota and the pathogen
as the most important antibiotic-associated diarrhea. This study aims to determine the gene expression of ...toxins A and B at the transcription level in the sub-MIC of vancomycin (VAN), clindamycin (CLI), and ceftazidime (CAZ) alone and in combination.
The MIC and fractional inhibitory concentration (FIC) of two
samples (a clinical isolate and ATCC 9689) were determined by microdilution and checkerboard microdilution methods, respectively. The total RNA was extracted from the medium inoculated with ∼10
CFU/mL of fresh bacteria in the pre-reduced medium containing ½ MIC of antibiotics alone and ½ FIC of antibiotics in combination. Real-time PCR was performed by sybrGreen methods in triplicate, and the data were analyzed by the comparative ΔΔ
method.
All antibiotics except CAZ (alone and in combination) decreased the gene expression of toxins A and B within 24 hours. VAN and CLI reduced toxin gene expression within 24 and 48 hours. However, CAZ alone and in combination with VAN as well as CLI increased the gene expression of toxins A and B.
The results confirmed toxin gene transcription and toxin production are associated with the type of isolates and antibiotics, as well as the combined form of antibiotics. This could be the reason which can explain the occurrence of
infection among patients who were treated with the third generation of cephalosporins alone and in combination with another antibiotic in the form of combinational therapy.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
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