MOLECULAR CHARACTERISTICS AND ANTIMICROBIAL RESISTANCE OF METHICILLIN RESISTANT STAPHYLOCOCCUS AUREUS ISOLATED FROM PIGS AND HUMANS IN KOGI STATE, NIGERIA

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dc.contributor.authorOTALU, Otalu Jnr
dc.date.accessioned2021-09-02T11:58:12Z
dc.date.available2021-09-02T11:58:12Z
dc.date.issued2021-02
dc.descriptionA THESIS SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES, AHMADU BELLO UNIVERSITY IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF DEGREE OF DOCTOR OF PHILOSOPHY IN VETERINARY PUBLIC HEALTH AND PREVENTIVE MEDICINE DEPARTMENT OF VETERINARY PUBLIC HEALTH AND PREVENTIVE MEDICINE, AHMADU BELLO UNIVERSITY, ZARIAen_US
dc.description.abstractStaphylococcus aureus is a common cause of serious community and health care-associated infections and limited antimicrobial treatment options for methicillin resistant Staphylococcus aureus (MRSA) infections make their management challenging. This study was conducted to determine the molecular characteristics and antimicrobial resistance of MRSA isolated from pigs and humans in Kogi State, Nigeria. Using standard microbiological techniques, 680 nasal swab samples collected from 425 pigs, 55 „in-contact‟ and 200 „non-contact‟ humans were analysed. Risk factors associated with MRSA carriage among humans was also determined using a structured questionnaire. Staphylococcus aureuswas recovered from 20 (4.7%) of the 425 pigs screened and 19 (7.5%) from humans. Six (2.4%) of the human S. aureus isolates were recovered from 55 „in-contact‟ while 13 (5.1%) were recovered from 200 „non-contact‟ humans. In addition 42 other isolates belonging to other Staphylococcus species (S. hyicus, S. scuiri, S. intermedius, S. lentus, S. chromogens, S. warnari, S. lugdunensis, S. saprophyticus, S. haemolyticus, S. xylosus) were recovered in the study. All of the S. aureus isolates (39; 100%) irrespective of source were resistant to β-lactams only. Also all of the S. aureusisolates had MIC values >4mg/ml for oxacillin and were termed methicillin resistant. Five (6.2%) and 3 (3.7%) of the other Staphylococcus species isolates from pigs and humans respectively showed multi-drug resistance patterns. Age and sex were found to be factors associated with nasal carriage of S. aureuswithin the study population. MRSA werecharacterized by a multiplex PCR to detect spa, mecA, lukF-PV(a marker of the Panton-Valentine leucocidin, PVL), scn and aCC398 specific band. Direct sequencing ofthe purified PCR reaction amplicon was used for spa typing. Four isolates (one pig, one pigcontact human fromthe same pig farm, one non-pig-contact human from the samedistrict, and one pig-contact human from a different district)were selected for further SCCmec, multilocus sequence typing and whole genomesequencing (WGS).All 39 MRSA isolates belonged to spa type t1603- sequence type (ST) 88, and mecA was associated with a SCCmecIVa element in 38/39 of the isolates. Core genome SNP analysis revealed high genetic similarity between strains (3-11 SNP differences), despite the temporal (2 year gap) and geographic (165km) differences between isolates. Furthermore, the MRSA isolates in this study form a distinct clade when compared with other African MRSA ST88 isolates. Nineteen (95%) of the porcine strains were positive for scnsuggesting a possible human origin and that pigs were either transiently contaminated by humans or result of a very recent human-to-pig transmission event.en_US
dc.identifier.urihttp://hdl.handle.net/123456789/12602
dc.language.isoenen_US
dc.subjectMOLECULAR CHARACTERISTICS,en_US
dc.subjectANTIMICROBIAL RESISTANCE,en_US
dc.subjectMETHICILLIN RESISTANT,en_US
dc.subjectSTAPHYLOCOCCUS AUREUS ISOLATED,en_US
dc.subjectPIGS AND HUMANS,en_US
dc.subjectKOGI STATE, NIGERIAen_US
dc.titleMOLECULAR CHARACTERISTICS AND ANTIMICROBIAL RESISTANCE OF METHICILLIN RESISTANT STAPHYLOCOCCUS AUREUS ISOLATED FROM PIGS AND HUMANS IN KOGI STATE, NIGERIAen_US
dc.typeThesisen_US
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