Prevalence of methicillin-resistant staphylococcus aureus carrying panton- valentine leukocidin gene in cutaneous infections in the city of Isfahan

Methicillin-Resistant Staphylococcus aureus [MRSA] is a major cause of Nosocomial and community infections that are becoming increasingly difficult to combat, because of emerging resistance to all classes of antibiotics. Moreover Panton-Valentine leukocidin [PVL] is an important virulence factor in S. aureus and causes white blood cell destruction, necrosis and accelerated apoptosis. The aim of this study was to determine the frequency of PVL-positive MRSA in cutaneous infections, for epidemiological purposes and also to determine antibiotic resistance of the isolates. Collectively, 56 isolates of S. aureus were obtained from Isfahan University of Medical sciences affiliated hospitals and confirmed with biochemical tests [coagulase, mannitol fermentation, and DNase]. Then polymerase chain reaction [PCR] was used to detect pvl gene. Coagulase gene was used as internal control. The antibiotic susceptibility of all isolates to methicillin was determined using disk diffusion method. Out of 56 isolates 14.3% were PVL positive that 37.5% were from abscess and 62.5% were from wound. Among all of these isolates 67.8% were MRSA and also 75% of PVL-positive isolates were MRSA. The prevalence of PVL positive MRSA in cutaneous isolates is high. Future works are necessary for a more complete understanding of distribution of these virulent isolates in nasal carriers to decrease the risk of infections.

Molecular identification and conventional susceptibility testing of iranian clinical mycobacterium fortuitum isolates

Rapidly growing mycobacteria [RGM] are capable of producing diseases in humans. Since mycobacteria vary in their susceptibility, precise identification is critical for adoption of correct drug therapy. The main aim of this study was molecular identification and evaluation of antimicrobial susceptibility pattern of Iranian clinically isolated Myocbacterium fortuitum. A total of 72 presumptively identified isolates of clinical atypical mycobacteria collected by Isfahan Research Center for Infectious Diseases and Tropical Medicine during 2006-2008 were included in the current study. A combination of conventional and molecular tests was applied to identify the isolates. Molecular methods including genus and group specific PCR and PCR-Restriction Algorithm [PRA] based on hsp65 gene were applied to achieve exact identification of mycobacterial strains. Antimicrobial susceptibility testing on M. fortidtum isolates was performed by in-house prepared broth microdilution test. Out of 72 collected atypical mycobacteria isolates, we identified 25 strains of M. fortuitum. All strains had the specific molecular markers of mycobacterial identity and similar species specific PRA pattern of the international type strain of M fortuitum. Drug susceptibility testing showed that the M. fortidtum isolates are sensitive to amikacin, sulfamethoxazole and ciprofloxacin [100%], imipenem [92%], clarithromycin [76%], cefoxitin [56%] and doxycycline [16%]. Molecular identification of atypical mycobacteria based on PRA is a reliable and rapid approach which can identify mycobacterial strains to the species level. Our study showed that M. fortuitum plays a significant role in pulmonary and extrapulmonary infection in patients and should be given proper considerations when clinical samples are processed

Comparison of PCR and culture methods for diagnosis of enteropathogenic campylobacter in fowl feces

Enteritis due to Campylobacter is the most common cause of acute bacterial diarrhea worldwide. In most cases, infection occurs as a result of consuming contaminated water or food, especially raw meat of fowls. Campylobacters are saccharolytic and fastidious bacteria. These traits limit the number of available biochemical tests by which isolates may be differentiated. These limitations might, in principle, be overcome by the use of PCR techniques, which is the aim of the present study. To compare the culture technique with PCR assay, a total of 116 fecal samples from fowls were tested using these two techniques for the presence of Campylobacters. Campylobacter strains were isolated from 11 [9.4%] out of 116 fecal cultures from fowls [8 C. jejuni and 3 C. coli]. Using PCR assays, the number of positive Campylobacters increased to 27 [23%]. Of these 27 positive samples, 18 were C. jejuni and 9 were C. coli. The sensitivity and specificity of PCR in comparison to the culture method were found to be 100 and 84.7%, respectively. According to the present study, it is proposed that the PCR is a reliable and sensitive method which can be used as a diagnostic technique for the detection of Campylobacter in fowls' samples