جستجوی مقالات مرتبط با کلیدواژه « Inducible Resistance » در نشریات گروه « پزشکی »

 Staphylococcus aureus is the most common agent of nosocomial infections. Macrolide Lincosamide-Streptogramin B (MLSB) antibiotics are the therapeutic choices for treatment of infections due to methicillin resistant S. aureus (MRSA) isolates. The most frequent mechanism for inducible resistance in S. aureus is modification in target site by erm (erythromycin ribosome methylase) genes.

 The aim of this research was to determine inducible MLSB (iMLSB) and detection the erm genes in clinical samples of S. aureus isolated from hospitalized patients in the Imam Reza hospital of Kermanshah, west of Iran.

 This study performed on 126 samples of S. aureus. Identification of isolates were performed using microbiological and biochemical procedures. Inducible resistance to clindamycin was tested by D-test. The prevalence of genes, such as femB, mecA, ermA and ermB was assessed by polymerase chain reaction (PCR).

 Eighty-three cases (65.9%) of isolates were methicillin resistant S. aureus (MRSA). The resistance rate against erythromycin and clindamycin was 67.4% and 52.2%, respectively. Totally, 49 cases (38.9%) of isolates were resistant to both erythromycin and clindamycin indicating constitutive MLSB phenotype (cMLSB); 20 cases (15.9%) isolates showed positive D test indicating inducible MLSB phenotype (iMLSB), while 16 cases (12.7%) were negative for D test indicating MS phenotype. Among 20 cases with iMLSB phenotype, ermC and ermA genes were showed in 7 cases (35%) and 4 cases (20%) isolates, respectively. The ermB gene is not detected in any cases and 9 cases (45%) isolates did not have any erm genes.

 In general, findings of this study showed high frequency of resistance to clindamycin and erythromycin among S. aureus isolates and cMLSB to be the most pattern phenotype and ermC gene is the most common gene in iMLSB phenotype. Because variation of antimicrobial resistance pattern in geographic regions obtaining local results is useful for detecting and more appropriate control of nosocomial infection due to S. aureus isolates.

Macrolide, lincosamide and streptogramin B (MLSB) are noteworthy antibiotics for the treatment of Staphylococcus aureus infections. The purpose of this study, was to determine the phenotypic and genotypic characterization of macrolide resistance, among S. aureus, isolated from clinical samples and nasal swabs.
Totally, 162 non-duplicate S. aureus isolates were collected from clinical samples and nasal swabs, from patients and healthcare workers (HCWs), between March 2016 and September 2016, at four teaching hospitals in Isfahan. The antibiotic resistance profile was determined using disk diffusion test and the presence of resistance genes was detected, using PCR.
Of 162 S. aureus isolates, 43.8% (71/162) and 34% (55/162) isolates were erythromycin-resistant and methicillin-resistant S. aureus (MRSA), respectively. The prevalence of constitutive MLSB (cMLSB), inducible MLSB (iMLSB), macrolide-streptogramin B-resistant (MSB) and lincosamide-streptogramin-A resistance (LSA) phenotype was 32%, 6%, 6% and 2%, respectively. The most common erythromycin resistance genes, in S. aureus isolates were ermC (35.2%), followed by ermA (20.4%) and msrA (17.3%). Meanwhile, msrA was detected in 43.6% of MRSA isolates. The frequency of coexistence of ermA窹苺欫, in S. aureus isolates was 7% and it was only detected in MRSA isolates.
In the current study, cMLSB phenotype was the most common erythromycin resistance pattern and ermC was the most prevalent gene in erythromycin-resistant isolates. The results revealed that the various mechanisms of erythromycin resistance are expanding in Isfahan.

The rising frequency of methicillin resistant Staphylococcus aureus (MRSA) has led to an increased use of antibiotics such as macrolide, lincosamide, streptogramin B (MLSB ) for the treatment of S. aureus infections. Resistance to MLSB in S. aureus is commonly encoded by erm genes, which can be constitutive MLSB (cMLSB ) or inducible MLSB (iMLSB ). The purpose of this study was to determine the frequency of cMLSB , iMLSB , and MS phenotypes using D‑test and polymerase chain reaction (PCR) methods.

A total of 215 isolates of S. aureus were collected from January 2010 to May 2012 from Al‑Zahra Hospital in Isfahan. PCR was performed for detection of mecA gene on all isolates using specific primers. The frequency of MLSB ‑resistant isolates was determined using D‑test, and then a multiplex PCR was performed for detection of ermA, ermB, and ermC genes.

Among 215 S. aureus isolates examined, 82 (40.9%) were MRSA, and iMLSB , cMLSB , and MS resistance phenotypes had a frequency of 9 (4.18%), 58 (26.9%), and 11 (5.1%), respectively. Among nine isolates with iMLSB resistance phenotype, four isolates contained ermC gene, two isolates ermB gene, and one isolate ermA gene. Two isolates did not have any erm gene.

In the current study, cMLSB was the most frequent phenotype and ermC was the most common gene in iMLSB resistant phenotypes.

Clindamycin inducible resistant Staphylococcus aureus (S.aureus) isolates can cause failure in treatment with this antibiotic. Biofilm production via polysaccharide intercellular adhesion (PIA) contributes in the colonization of S. aureus, resulting in the initiation of different diseases. The aim of this study was to detect icaADBC genes among isolates of S.aureus with inducible resistance to clindamycin.
A total of 209 clinical S.aureus isolates werecollected and identified by conventional phenotypic tests. Isolates with inducible resistance to clindamycin were detected by double disk diffusion test (D-Test) using clindamycin (2 μg) and erythromycin (15 μg). Oxacillin was used to detect Methicillin resistant Staphylococcus aureus (MRSA) isolates. Polymerase Chain Reaction (PCR) was performed to detect the icaADBC genes.
The rate of clindamycin inducible resistance was 4% (n=8). All the isolates were susceptible to methicillin. Four isolates (50%) contained the whole icaADBC genes. The prevalence of icaA, icaB, icaC and icaD genes were 5 (62.5%), 4 (50%), 6 (75%) and 5 (62.5%), respectively.
The results indicate that the prevalence of icaADBC genes among clindamycin inducible resistant strains was low, and also these strains were susceptible to methicillin.

Staphylococcusaureus is a prominent human pathogen. One of the drugs used in the treatment of staphylococcal infections (particularly infections of skin and soft tissue), is clindamycin. Resistance to clindamycin includes two types: inducible and constitutive. Routine laboratory methods of antibiotic susceptibility testing cannot detect the inducible type and D-test is required for its detection. The purpose of this systematic review was to determine the relative prevalence of this type of resistance in Iran. Search terms «inducible clindamycin resistant», «D-test», «Staphylococcus aureus» and «Iran» were used to find relevant articles in PubMed, Google Scholar and two Persian search engines. Also, the abstracts of the recent national microbiology congresses were checked. All studies used D-test to find iMLSB (inducible macrolide, lincosamide and streptograminB resistance) phenotype among clinical isolates (not nasal swabs) of S. aureus, were included. In order to perform meta-analysis, we used “comprehensive meta-analysis” software (ver. 2). In total, 9 articles and 8 abstracts related to the topic of the study were found. Random effects meta-analyses showed a pooled estimate for percentage of iMLSB phenotype among 2683 samples of S. aureus was about 10% (95% confidence interval: 0. 07-0. 12). Using the fixed effect model, the odds of positive iMLSB in methicillin-resistant S. aureus was about 5 times more likely to occur in comparison with methicillin-susceptible S. aureus (95% CI: 3. 49 to 7. 76). Fortunately, the relative frequency of inducibleresistance to clindamycin in our country is relatively low. However, we believe that D-test should be performed for all erythromicin-resistant isolates in order to identify inducible resistance to clindamycin. Moreover, reevaluation of inducible resistance to clindamycin in forthcoming years is highly recommended.

Streptococcus group B (GBS) or Streptococcus agalactiae is typically associated with neonatal disease and infection in pregnant women. Mortality of GBS sepsis in neonates is over 50% and is particularly high in preterm infants. GBS also causes invasive infection in pregnant and non-pregnant women including urinary tract infection (UTI). Penicillin-derived antibiotics remained as choice drugs for treatment of GBS infection; however, Erythromycin and Clindamycin are useful in cases of allergic to Penicillin. The aim of this study was to investigate the resistance to Erythromycin and Clindamycin, especially inducible Clindamycin resistance, in GBS isolated from urinary samples of women who attended medical offices in Tehran, Iran. This study was conducted on 5000 urine samples from Jan. 2011 to Oct. 2012 that 104 GBS were isolated. The isolates were identified as GBS using laboratory criteria. Antimicrobial susceptibility test was done by Erythromycin disk 15µg and Clindamycin disk 2µg for observation inducible resistant D-zone test by double-disk diffusion method with Erythromycin and adjacent Clindamycin. Among the 5000 urine samples 104 (2.08%) were Beta hemolytic GBS. Of the 104 isolated GBS, 22 (21.2%) were resistance, 24 (23%) were intermediate, and 58 (55.8%) were susceptible to Erythromycin; however, 24 (23%) were resistance, 5 (4.8%) were intermediate, and 75 (72.2%) were susceptible to Clindamycin. Of the 22 Erythromycin-resistant isolates, 10 (9.5% in total GBS isolated) displayed the D zone; it means they have inducible Erythromycin resistant to Clindamycin. Various studies in other countries report lower rates of inducible Clindamycin resistance; it indicates the use of more macrolides in the treatment of UTI.

Clindamycin is a frequently used antimicrobial therapeutic medicine used for the treatment of skin and soft tissue infections caused by Staphylococcus aureus strains. Resistance to this antibiotic is either constitutive or inducible. Constitutive resistance to clindamycin could be detected by standard susceptibility testing methods. Inducible clindamycin resistance could not be detected by in vitro routine tests. This type of resistance can be identified by D-test.. The outbreak of inducible resistance to clindamycin in methicillin resistant and-susceptible S. aureus isolates were investigated in this study.. Totally 162 S. aureus isolates were evaluated for inducible clindamycin resistance by D-test in accordance with clinical and laboratory standards institute (CLSI) guidelines.. Inducible clindamycin resistance was detected in 8.64% of S. aureus isolates. Inducible and constitutive resistance to clindamycin was found to be higher in methicillin resistant S. aureus (11.95% and 47.8% respectively) compared to methicillin susceptible S. aureus (4.28% and 2.85% respectively) isolates.. Our results showed that inducible resistance to clindamycin in S. aureus isolates is relatively higher in this region. Therefore, D-test should be performed to prevent treatment failures against infections caused by S. aureus, which are resistant to erythromycin and the sensitive ones against clindamycin..

Staphylococcus aureus is an important agent in hospital and community-associated infections, causing high morbidity and mortality. Introduction of the new antimicrobial classes for this pathogen is usually followed by the emergence of resistant strains through multiple mechanisms. For instance, resistance to clindamycin (CLI), can be constitutive or inducible. Inducible clindamycin resistance which may lead to treatment failure can simply be identified by performing D-test. The aim of this study was to determine the prevalence of inducible clindamycin resistance among Staphylococcus aureus isolates by D-test method. This was a cross-sectional study conducted on 254 non-duplicated S. aureus isolates in Imam Reza hospital of Mashhad during 2010. Susceptibility to oxacillin, cefoxitin, erythromycin and clindamycin was performed by disk agar diffusion method according to CLSI guidelines and D-shaped clindamycin susceptibility patterns where considered as D-test positive (D+). Of 211 S. aureus isolates 88 (37.82%) were methicillin resistant. It was found that of 88 MRSA isolates, 78 (88.63%) were erythromycin (ERY) resistant and 46 (52.27%) were CLI resistant. ERY and CLI resistance in MSSA strains was 21.95% and 11.96% respectively. Inducible clindamycin resistance was detected in 18 (20.45%) MRSA isolates. 47(53.40%) of MRSA isolates and 9 (7.32%) of MSSA showed constitutive MLSB phenotype. In conclusion, we found a high prevalence of inducible clindamycin resistance phenotype in our region. We recommend that whenever clindamycin is intended for S. aureus infections, D-test should be performed to facilitate the optimal treatment of patients.