Prevalence and antibacterial resistance patterns of uropathogenic staphylococci in Casablanca, Morocco.

INTRODUCTION: The purpose of this research is to evaluate the resistance profile of uropathogenic staphylococci bacteria in Casablanca, Morocco. METHODOLOGY: In this retrospective cross-sectional research carried out from January 2017 to December 2020, isolation and identification were carried out according to the usual techniques in medical microbiology. Staphylococcus aureus isolates were confirmed by polymerase chain reaction (PCR) amplification of the nuc gene, and the antibiogram was performed according to the guidelines of the Antibiogram Committee of the French Society of Microbiology (CA-SFM 2021). The susceptibility of uropathogenic staphylococci to vancomycin was determined with broth microdilution following the recommendations of the Clinical and Laboratory Standards Institute. The mecA gene was tested on phenotypically cefoxitin-resistant S. aureus isolates by PCR. RESULTS: The prevalence of urinary tract infections (UTIs) was 18% (772/4374). UTIs were more common in females (n = 483, 63%) than males (n = 289, 37%). Among the Gram-positive bacteria isolated (198, 25.65%), the prevalence of staphylococci was (130/198, 65.66%). Among staphylococcal species identified, coagulase-negative staphylococci (CoNS) were more prevalent (112/130, 86.15%), and Staphylococcus saprophyticus was the most frequently isolated CoNS (46/112, 41.07%). Additionally, there were several S. aureus strains (18/130, 13.85%). Forty-four percent of S. aureus isolates (n = 8) were resistant to cefoxitin and also harboured the mecA gene. All S. aureus isolates were susceptible to linezolid, cotrimoxazole and vancomycin. CONCLUSIONS: The prevalence and antibacterial resistance patterns of uropathogenic staphylococci in this study, with a high percentage of methicillin resistance, require careful consideration of antimicrobial therapy for staphylococcal UTIs.

Genotypic diversity of multi- and pre-extremely drug-resistant Mycobacterium tuberculosis isolates from Morocco.

In Morocco, the prevalence of multidrug resistant tuberculosis (MDR-TB) continues to increase especially within previously treated cases; these MDR cases may evolve to extensively drug resistant tuberculosis (XDR-TB) raising major concern to TB control programs. From an epidemiological window, scarce informations are available about the genetic diversity of Mycobacterium tuberculosis (MTB) strains fueling these forms of resistance. The aim of this study was to assess to genetic diversity of MDR-MTB strains. Hence, this prospective study was conducted on patients diagnosed with MDR-TB at Pasteur Institute of Casablanca from 2010 to 2013. A total of 70 MDR-MTB isolates were genotyped by spoligotyping and 15-loci MIRU-VNTR methods. Spoligotyping generated four orphan patterns, five unique profiles whereas 61 strains were grouped in nine clusters (2 to 25 strains per cluster), the clustering rates being 87.1%. Subtyping by 15 loci MIRU-VNTR splitted all clusters already established by spoligotyping and generated 70 unique profiles not recognized in SITVIT2 database; clustering rate was equal to zero. HGDI analysis of 15 loci MIRU demonstrated that eight out of 15 loci were highly discriminant. Of note, all pre-XDR strains belongs to many clades, meaning that there no association between gyrA mutants and particular clade. Overall, the data generated by this study (i) describe the population structure of MDR MTBC in Morocco which is highly homogenous, (ii) confirm that TB in Morocco is almost exclusively transmitted by modern and evolutionary lineages with high level of biodiversity seen by MIRU, and (iii) validate the use of optimized 15-loci MIRU-VNTR format for future investigations in Morocco.

Molecular characterization of mutations associated with resistance to second line drugs in Mycobacterium tuberculosis patients from Casablanca, Morocco.

The emergence and spread of extensively drug-resistant tuberculosis (XDR-TB) is a serious threat to global health. Therefore, its rapid diagnosis is crucial. The present study aimed to characterize mutations conferring resistance to second line drugs (SLDs) within multidrug Mycobacterium tuberculosis (MDR-MTB) isolates and to estimate the occurrence of XDR-TB in Casablanca, Morocco. A panel of 200 MDR-TB isolates was collected at the Pasteur Institute between 2015-2018. Samples were subjected to drug susceptibility testing to Ofloxacin (OFX), Kanamycin (KAN) and Amikacin (AMK). The mutational status of gyrA, gyrB, rrs, tlyA and eis was assessed by sequencing these target genes. Drug susceptibility testing for SLDs showed that among the 200 MDR strains, 20% were resistant to OFX, 2.5% to KAN and 1.5% to AMK. Overall, 14.5% of MDR strains harbored mutations in gyrA, gyrB, rrs and tlyA genes. From the 40 OFXR isolates, 67.5% had mutations in QRDR of gyrA and gyrB genes, the most frequent one being Ala90Val in gyrA gene. Of note, none of the isolates harbored simultaneously mutations in gyrA and gyrB genes. In eight out of the 200 MDR-TB isolates resistant either to KAN or AMK, only 25% had A1401G or Lys89Glu change in rrs and tlyA genes respectively. This study is very informative and provides data on the alarming rate of fluoroquinolone resistance which warrants the need to implement appropriate drug regimens to prevent the emergence and spread of more severe forms of Mycobacterium tuberculosis drug resistance.