Distribution of sasX, qacA/B and mupA genes and determination of genetic relatedness of methicillin-resistant Staphylococcus aureus among clinical isolates and nasal swab samples from the same patients in a hospital in Malaysia

INTRODUCTION

This study determined the distribution of sasX, qacA/B and mupA genes from methicillin-resistant Staphylococcus aureus (MRSA) isolated from clinical samples and nasal swab samples of the same patients and analysed their genetic relatedness.

METHODS

Polymerase chain reaction (PCR) was used to detect the presence of sasX, qacA/B and mupA genes from 47 paired MRSA isolates. A paired isolate was defined as one nasal swab (colonising) isolate and clinical isolate that caused infection in the same patient. 22 selected paired isolates were subjected to multilocus sequence typing (MLST). The genetic relatedness among the isolates and association between the putative genes with epidemic sequence types (STs) were investigated.

RESULTS

7 (14.9%, n = 14) paired isolates were positive for the sasX gene. qacA/B genes were positive in 7.4% (n = 7) of the isolates, from three paired isolates and one clinical isolate whose paired colonising isolate was negative. The paired sample of three patients were positive for both genes. The mupA gene was not detected in all the isolates. MLST revealed two epidemic STs, ST22 and ST239, and a novel ST4649. sasX and qacA/B genes were found in ST239 in 29.5% (n = 13) and 13.6% (n = 6) of cases, respectively. Gene co-existence occurred in 13.6% (n = 6) of MRSA ST239 and 2.3% (n = 1) of MRSA ST4649.

CONCLUSION

sasX and qacA/B genes were present in the MRSA isolates, while the mupA gene was undetected. ST22 and ST239 were the major MRSA clones. The circulating MRSA genotypes conferred different virulence and resistance determinants in our healthcare settings.

Phenotypic and genotypic characterization of macrolide, lincosamide and streptogramin B resistance among clinical isolates of staphylococci in southwest of Iran

Objective

The present study aimed to determine the phenotypic and genotypic profile of macrolide, lincosamide and streptogramin B (MLS_B) resistance in clinical isolates of staphylococci.

Results

This cross-sectional study was conducted on 164 non-duplicated staphylococci isolates collected during August 2015 to February 2016 from two tertiary care hospitals in Shiraz, southwest of Iran. Of the 164 isolates, 86 erythromycin-resistant isolates consist of 35 Staphylococcus aureus and 51 coagulase negative staphylococci (CoNS) were included in the study. Of the 35 S. aureus, the prevalence of cMLS (constitutive), iMLS (inducible), and MS phenotypes were found 82.9%, 8.6% and 8.6%, respectively. Among 51 CoNS, the frequencies of cMLS, iMLS, and MS phenotypes were detected 66.7%, 11.8% and 21.6%, respectively. Among S. aureus isolates, the predominant genes were ermC in 82.9% isolates, followed by ermA in 57.1% and msrA in 28.6% of isolates. Among CoNS isolates, the most frequent genes were diagnosed ermC in 70.6% isolates followed by msrA in 68.6% and ermA in 11.8% of isolates. In conclusion, regarding the presence of MLS_B resistance in our region, diagnosis of this resistance type on a routine basis in staphylococcal clinical isolates is of particular importance.

The Occurrence of Nosocomial Pathogens on Cell Phones of Healthcare Workers in an Iranian Tertiary Care Hospital

BACKGROUND

Cell phones have become one of the necessary means of life and they are commonly used almost everywhere by every population. Colonized microorganisms on cell phones can be easily cross-transmitted. Given the widespread prevalence of nosocomial infections, this study aimed to determine the frequency of bacterial contamination and antibiotic resistance in cell phones of healthcare workers (HCWs) in a tertiary care hospital, from southwest of Iran. In this cross-sectional study conducted between April and June 2016, sampling were performed from cell phones of 25 nurses and 75 medical students.

METHODS

Samples were collected from each cell phone by a moistened cotton swap dipped in normal saline prior and after decontamination with available alcohol-based handrubs. Identification of bacterial isolates was performed by conventional microbiologic methods. Antibiotic susceptibility pattern of the isolates was determined using the disk diffusion method. The contamination rates of cell phones prior and after disinfection were 88% and 52%, respectively. Ninety-nine (71.2%) out of 139 isolated distinct bacterial colonies prior to cleaning were potentially nosocomial pathogens. Of them, staphylococci (88.9%) were the most prevalent bacteria, in which 40.9% were methicillin-resistant isolates. The majority of Gram-positive and - negative isolates were susceptible to the tested antimicrobials. Totally, contamination rate of cell phones was significantly reduced after decontamination. Regular disinfection of the hands and cell phones was significantly associated with reduction of colonization of the methicillin-resistant isolates.

RESULT & CONCLUSION

These findings emphasize the restricted use of cell phones and encourage the higher compliance with hygienic practices in hospitals to reduce the risk of nosocomial infections.