Background: Staphylococcus aureus is one of the most important agents causing nosocomial infections. INDUCIBLE CLINDAMYCIN RESISTANCE is an important concern, because common laboratory tests could not detect it.Objectives: The aim of this study was to detect the INDUCIBLE CLINDAMYCIN RESISTANCE by D-test method. Materials and Methods: A total of 209 clinical S. aureus isolates were collected and identified by conventional phenotypic tests. Antibiotic susceptibility pattern was detected by disc diffusion method. D-test was done using CLINDAMYCIN (2 mg) and erythromycin (15 mg) discs according to the protocols of Clinical and Laboratory Standards Institute (CLSI). To detect methicillin resistant Staphylococcus aureus (MRSA), oxacillin disc was used and the results were confirmed by detection of mecA gene.Results: Of all 209 clinical S. aureus isolates, 207 (99%) were resistant to amoxicillin. All isolates were susceptible to vancomycin and linezolid. The rate of CLINDAMYCIN INDUCIBLE RESISTANCE was 4% (n=8). This phenotype was not observed in MRSA strains. There was no significant difference between methicillin resistant and susceptible strains. RESISTANCE to CLINDAMYCIN and erythromycin was higher in MRSA strains. D+ phenotype was detected in 1 (1%) of all isolates. Methicillin RESISTANCE was detected in 66 (32%) isolates by oxacillin disc and mecA gene was detected by PCR. Conclusions: In our study, INDUCIBLE CLINDAMYCIN RESISTANCE rate was 4%; so it is necessary to conduct D-test regularly by disc diffusion for this bacterium. RESISTANCE to erythromycin, CLINDAMYCIN, ciprofloxacin and gentamicin was significantly higher in MRSA isolates than methicillin susceptible Staphylococcus aureus (MSSA), although the methicillin RESISTANCE prevalence was low.

Background: Staphylococcus aureusis the most common agent of nosocomial infections. Macrolide Lincosamide-Streptogramin B (MLS B) 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. aureusis modification in target site by erm( erythromycin ribosome methylase) genes. Objectives: The aim of this research was to determine INDUCIBLE MLSB (iMLS B) and detection the ermgenes in clinical samples of S. aureusisolated from hospitalized patients in the Imam Reza hospital of Kermanshah, west of Iran. Methods: 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, ermAand ermBwas assessed by polymerase chain reaction (PCR). Results: 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 (cMLS B); 20 cases (15.9%) isolates showed positive D test indicating INDUCIBLE MLSB phenotype (iMLS B), while 16 cases (12.7%) were negative for D test indicating MS phenotype. Among 20 cases with iMLS Bphenotype, ermCand ermAgenes were showed in 7 cases (35%) and 4 cases (20%) isolates, respectively. The ermBgene is not detected in any cases and 9 cases (45%) isolates did not have any ermgenes. Conclusions: In general, findings of this study showed high frequency of RESISTANCE to CLINDAMYCIN and erythromycin among S. aureusisolates and cMLS Bto be the most pattern phenotype and ermCgene is the most common gene in iMLS Bphenotype. 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. aureusisolates.

Background and Objectives: 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 has been 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.Materials and Methods: This was a cross-sectional study conducted on 211 non-duplicated S. aureus isolates in Imam Reza hospital of Mashhad during 2010. Susceptibility to oxacillin, cefoxitin, erythromycin and CLINDAMYCIN was performed by agar disk diffusion method according to CLSI guidelines and D-shaped CLINDAMYCIN susceptibility patterns where considered as D-test positive (D+).Results: Of 211 S. aureus isolates, 88 (41.7%) were methicillin resistant. It was found that of 88 MRSA isolates, 78 (88.6%) were erythromycin (ERY) resistant and 46 (52.3%) were CLI resistant. ERY and CLI RESISTANCE in MSSA strains was 22% and 11.4% respectively. INDUCIBLE CLINDAMYCIN RESISTANCE was detected in 18 (20.5%) MRSA isolates, 46 (52.3%) of MRSA isolates and 9 (7.3%) of MSSA showed constitutive MLSB phenotype.Conclusion: In conclusion, we found a high prevalence of INDUCIBLE CLINDAMYCIN RESISTANCE phenotype in our region. We recommend that whenever CLINDAMYCIN is intended to be used for S. aureus infections, D-test should be performed to facilitate the appropriate treatment of patients.

Objective: Methicillin resistant staphylococcus aureus (MRSA) is a frequent cause of infections in children. The purpose of this study was to determine the frequency of nasal colonization of S. aureus in children and detection of INDUCIBLE CLINDAMYCIN RESISTANCE (ICR) by disk approximation test (D-test).Methods: This was a cross-sectional study conducted in Hamedan from 2007 to 2008. 520 nasal swabs were obtained from children under 12 years of age at the time of admission and 287 swabs at the time of discharge. Antibiogram was performed by method of disk diffusion for oxacillin, erythromycin, CLINDAMYCIN, cefazolin and vancomycin as well as D-test. Chi-square test was applied for statistical analysis.Findings: Out of 520 patients, 118 (22.3%) were colonized with S. aureus as community acquired (CA-S.aureus). Of 287 patients, 64 (22.3%) were colonized with isolates of S. aureus at discharge time. Of these 64 patients, 32 cases were colonized with hospital acquired (HA-S. aureus) isolates after admission. Only one CA-MRS Aisolate was resistant to CLINDAMYCIN, 5% of 118 (A-S. aureus isolates and 6.3% of HA-S. aureus isolates had INDUCIBLE CLINDAMYCIN RESISTANCE (D-test). Also 37.5% of CA-MRS Aisolates at the time of admission and 22.2% of HAMRS Aisolates at discharge had positive D-test.Conclusion: We emphasize that D-test should be used routinely and CLINDAMYCIN should not be used in patients with .infections caused by INDUCIBLE resistant S.aureus.

Background & Objectives: Macrolide, lincosamide and streptogramin B (MLSB) antimicrobial agents are used in the treatment of staphylococcal infections. They prevent the microbial protein synthesis system through binding to 23SrRNA. The aim of this study was to apply molecular methods to detect INDUCIBLE CLINDAMYCIN RESISTANCE genes among staphylococcal strains isolated from clinical specimens.Methods: Two hundred staphylococcus strains were isolated from nose and throat swabs of patients in Toohid and Besat hospitals in Sanandaj. Antimicrobial susceptibilities of isolates were determined using disc diffusion method, agar screen test and D-Test. A multiplex PCR was performed using primers specific for erm (A, B, C, TR) genes.Results: Out of 200 isolates, 18.5 % were MRSA and 32% were MRCNS (methicillin resistant coagulase negative staphylococci). Of 80 erythromycin resistant isolates, 48 were coagulase negative and 32 were S. aureus. Among the 48 coagulase negative staphylococci (CONS) isolates, 11.63% expressed the MLSB-INDUCIBLE phenotypes. Using PCR, the frequency of different genes in the collection of isolates were as follows: erm A, 5.41 %, erm B, 5.41 %, and erm C, 3.13%. The ermTR gene was negative in all isolates. Among the 32 S. aureus isolates, 9.38% expressed the MLSB-nducible phenotype. Using PCR, these isolates harbored erm A (2.22%), ermB (2.22%), ermC (2.22%) and ermTR (2.22%).Conclusion: This is the first study to show the rate of INDUCIBLE CLINDAMYCIN clinical isolates of staphylococci harboring erm genes in Sananadaj. It also demonstrated the frequency of erm genes was higher among CONS isolates than S. aureus. This data suggested the transfer of RESISTANCE gene from nonpathogenic to pathogenic strains is likely to happen. Therefore, screening and control of these RESISTANCE genes is recommended at clinical laboratories.

Background: 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.Materials and Methods: 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.Results: 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.Conclusion: Various studies in other countries report lower rates of INDUCIBLE CLINDAMYCIN RESISTANCE; it indicates the use of more macrolides in the treatment of UTI.