Iranian CA-MRSA strains are genetically diverse with an elevated prevalence of t790/ST22 SCCmec IV isolates. These findings support the need for more effective infection control measures to reduce nasal carriage and prevent dissemination of CA-MRSA in Iran.

Background:Klebsiella pneumoniae is among the most frequently recovered etiologic agents from nosocomial infections. This opportunistic pathogen can generate a thick layer of biofilm as one of its important virulence factors, enabling the bacteria to attach to living or abiotic surfaces, which contributes to drug resistance.Objectives:The resistance of biofilm-mediated infections to effective chemotherapy has adverse effects on patient outcomes and survival. Therefore, the aim of the present study was to evaluate the biofilm-formation capacity of clinical K. pneumoniae isolates and to perform a molecular characterization using enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) to determine the dominant biofilm-producing genotype.Patients and Methods:In the present study, 94 K. pneumoniae isolates were obtained from two hospitals in Tehran, Iran. Biofilm formation was assayed by a modified procedure, then ERIC-PCR was carried out.Results:The distributions of the clinical specimens used in this study were 61.7% from urine, 18.1% from wounds, 11.7% from sputum, and 8.5% from blood. Among these isolates, 33% formed fully established biofilms, 52.1% were categorized as moderately biofilm-producing, 8.5% formed weak biofilms, and 6.4% were non-biofilm-producers. Genotyping of K. pneumoniae revealed 31 different ERIC types. Biofilm-formation ability in a special ERIC type was not observed.Conclusions:Our results indicated that an enormous proportion of K. pneumoniae isolated from sputum and surgical-wound swabs produced fully established biofilms. It is reasonable to assume the existence of a relationship between the site of infection and the formation of biofilm. A high level of genetic diversity among the K. pneumoniae strains was observed.

Introduction: Chamomile (Chamaemelum nobile) is widely used throughout the world, and has anti-infl ammatory, deodorant, bacteriostatic, antimicrobial, carminative, sedative, antiseptic, anti-catarrhal, and spasmolytic properties. Because of the increasing incidence of drug-resistant bacteria, the development of natural antibacterial sources such as medical herbs for the treatment of infectious diseases is necessary. Extracts from different plant parts such as the leaves, fl owers, fruit, and bark of Combretum albifl orum, Laurus nobilis, and Sonchus oleraceus were found to possess anti-quorum sensing (QS) activities. In this study, we evaluated the effect of C. nobile against Pseudomonas aeruginosa biofi lm formation. Methods: The P. aeruginosa samples were isolated from patients with different types of infection, including wound infection, septicemia, and urinary tract infection. The fl owers of C. nobile were dried and the extract was removed using a rotary device and then dissolved in dimethyl sulfoxide at pH 7.4. The microdilution method was used to evaluate the minimum inhibitory concentration (MIC) of this extract on P. aeruginosa, and biofi lm inhibition was assayed. Results: Eighty percent of the isolated samples (16/20) could form a biofi lm, and most of these were isolated from wound infections. The biofi lm inhibitory concentration of the C. nobile extract was 6.25-25mg/ml, whereas the MIC was 12.5-50mg/ml. Conclusions: The anti-QS property of C. nobile may play an important role in its antibacterial activity, thus offering an additional strategy in the fi ght against bacterial infections. However, molecular investigation is required to explore the exact mechanisms of the antibacterial action and functions of this phytocompound.

Objectives: Drug resistance among gram-negative bacteria is a worldwide challenge. Due to the importance of drug-resistant Klebsiella pneumoniae and Escherichia coli strains in hospital-acquired infections, we aimed to determine the phenotypic and genotypic characteristics of ESBL-, AmpC-, and carbapenemase-producing isolates obtained from hospitalized patients in Tehran and Ilam (Iran). Materials and Methods: In total, 90 K. pneumoniae isolates and 65 E. coli isolates were collected from various infections. Phenotypic identification of bacterial isolates was performed using standard methods. Phenotypic screening of ESBL, AmpC, and carbapenemase enzymes was carried out. Detection of ESBL, AmpC, and carbapenemase genes was also performed by the PCR method. Results: Phenotypic detection tests showed that 36 (40%) K. pneumoniae and 23 (35.4%) E. coli isolates were ESBL producers. Moreover, 18 (20%) and 6 (9.2%) K. pneumoniae and E. coli isolates were AmpC producers, respectively. Modified Hodge test results indicated that 39 (43.3%) K. pneumoniae and 18 (27.7%) E. coli isolates produced carbapenemase. Molecular tests showed that 40% of K. pneumoniae and 36.9% of E. coli isolates were ESBL positive. AmpC was detected in 24.4 and 13.8% of K. pneumoniae and E. coli isolates. Carbapenemase was detected in 34 (37.8%) K. pneumoniae and 13 (20%) E. coli isolates. ­Conclusion: In this study, 3 K. pneumoniae isolates simultaneously carried ESBL, AmpC, and carbapenemase genes. Up-to-date strategies such as combination therapy or utilization of new antimicrobial agents might help to combat such drug-resistant organisms.

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BackgroundStaphylococcus aureus is one of the most important causative agents in community- and hospital-acquired infections. Aminoglycosides are powerful bactericidal drugs that are often used in combination with beta-lactams or glycopeptides to treat staphylococcal infections.ObjectivesThe main objective of the present study was to determine the prevalence of aminoglycoside resistance among methicillin-resistant Staphylococcus aureus (MRSA) isolates in hospitalized patients in Sari and Tehran, Iran.MethodsIn this study, 174 MRSA strains isolated from different clinical samples, such as blood, sputum, tracheal exudates, bronchus, pleura, urine, wounds, and catheters, were collected from hospitalized patients in Tehran and Sari during 2014. Antibiotic susceptibility testing was performed against nine antibiotics with the Kirby-Bauer disk diffusion method according to CLSI guidelines. The MRSA strains were examined with oxacillin and cefoxitin disks. MRSA was then validated by detection of the mecA gene. PCR was used to evaluate the prevalence of the aminoglycoside-resistance genes aac (6’)-Ie/aph (2”), aph (3’)-IIIa, and ant (4’) among the MRSA isolates.ResultsThe results of drug susceptibility testing showed that the highest rate of resistance was against erythromycin in Tehran (84.4%) and gentamicin (71.7%) in Sari. All isolates were sensitive to vancomycin, and all strains harbored the mecA gene. The aac (6’)-Ie/aph (2”), aph (3’)-IIIa, and ant (4’)-Ia genes were detected among 134 (77%), 119 (68.4%), and 122 (70.1%) of the isolates, respectively.ConclusionsThe present study showed a high prevalence of aminoglycoside-resistance genes among MRSA isolates in two cities in Iran.

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