Approximately 20-30% of healthy persons are persistent carriers of S. aureus and 60% are intermittent carriers with high colonization rates among risk groups including hospital patients, children’s and jail inmates [13, 14]. In the present study, a total of 354 nasal swabs were collected from 304 primary school children and 50 prisoners. The frequency of isolation of S. aureus from primary school children of Jimma town was 47.3%, with an overall frequency of isolation being 47.74% (169/354). In a related study, Yildirim et al.  also reported an isolation rate of 37% from nasal swabs of primary school children aged 6–14 years. According to Rijal, et al. , the rate of isolation of S. aureus from school children was 31%. The relatively low isolation rate reported in the later two studies could be due to the direct inoculation of the nasal swabs on Mannitol salt agar without primary and secondary enrichment which may reduce the possible isolation rate of the organism. According to the present study, the isolation rate of S. aureus from among prisoner was 50%. Worldwide isolation rate of S. aureus from among prisoners was reported to range from 40.5% to 78% [13, 14].
In the present study, the prevalence of MRSA among primary school children aged 5–15 years was 18.8%. Here, MRSA was detected using Cefoxitin (30μg) disc which has high efficiency to detect MRSA and has been used as an alternative to PCR in resource constrain areas [12, 16]. Alfaro et al.  also reported 22% carriage rate of MRSA among children of south Texas. The findings of this study was in agreement with earlier studies reported from different parts of the world [10, 12].
The prevalence of MRSA among prisoners of Jimma town was 48%, the first report of its kind from Ethiopia. A recent report from Philippine showed 41% prevalence of MRSA among inmates of Manila city jail . In another study conducted at California, the prevalence of MRSA was reported to be 54% . In the present study, high nasal colonization of S. aureus and MRSA among primary school children and prisoners could be accounted to the associated risk factors. The main risk factors for primary school children of the study area were age, sex, number of children per class room, child’s and family member’s previous year hospitalization. As clearly shown in the result section, S. aureus (p=0.000) and MRSA (p=0.016) nasal carriage was significantly associated to the number of children per class room with the highest prevalence of S. aureus (30.6%, p=0.011) and MRSA (48%, p=0.027) being in class rooms where the number of children was greater than 60. Furthermore, MRSA nasal carriage was the highest among children that came from households with 5–6 family members. A similar study indicated that S. aureus and MRSA nasal carriage is the highest (62.06%) among students belonging to age group of 6–10 .
The current study shown that MRSA nasal carriage was the highest among female children compared to male children (23[85.2%] Vs 4 [14.8%]; p=0·000). Similarly, Rijal, et al.  reported higher prevalence of MRSA in female children than males (22[68.7%] Vs 10[31.3%]). In the study conducted at Primary School in Düzce, Turkey, Yildirim, et al.  also reported higher prevalence of MRSA among female children when compared to male counterpart.
In this study, 29.6% of MRSA strains were isolated from children that had history of previous year hospitalization (p=0.007) and also 14.8% from children that had family member hospitalized in previous year (p=0.041). Many internationally accepted definitions of hospital acquired MRSA (HA-MRSA) emphasize the isolation of MRSA from an individual that has history of previous year hospitalization [19–22]. Therefore, isolation of MRSA from an individual that had risk factor of HA-MRSA in the present study and other similar reports of high prevalence of MRSA from outpatient and healthy staff member [9, 23] could indicate the dissemination of HA-MRSA from hospital to the community outside hospital. Such condition contributes to high prevalence of MRSA outside hospitals.
As compared to the school children, Epidemiologic risk factors that have significant association with MRSA nasal carriage among prisoners were: high number of prisoners (>60) per dormitory/room (p=0.0340), antibiotic usage (p= 0.01) and presence of respiratory infection (p=0.005). Similar studies showed that the rate of nasal colonization of MRSA is high when there are predisposing risk factors like antibiotic usage in previous 4 weeks and presence of respiratory infection during sample collection which was supposed to be risk factors for HA-MRSA [13, 24].
All S. aureus isolates showed 100% resistance to Penicillin. Similarly, MRSA isolates showed 100% resistance to Ampicillin, Penicillin and Cefoxitin. In agreement with this observation, Gabriel and Kebede also reported 100% resistance of S. aureus isolated from among Health Workers of Jimma University Specialized Hospital . Likewise, Uwaezuoke and Aririatu  reported high resistance to Penicillin (95.8%) of S. aureus strains isolated from clinical sources in Owerri, Nigeria. The absolute resistance of MRSA isolates to these antibiotics indicates the dissemination and dominance of HA-MRSA in the community, hence CA-MRSA strains, capable of resisting only β- lactam antibiotics as the result of carriage of genetic element SCCmec typeIV. SCCmec type IV is one of the shorter SCCmec variations less likely to carry multi-drug resistance . Significant proportions of MRSA isolates (87.2%) were susceptible to Vancomycin (p=0.000), Gentamycin (84.6%) (p=0.006) and Trimethoprim-sulfamethoxazole (82.1%) (p= 0.000). Among S. aureus isolates, 97% were susceptible to Vancomycin, 95.3% to Gentamycin and 94.7% to Trimethoprim-sulfamethoxazole. In review of similar work, Uwaezuoke and Aririatu  reported the degree of susceptibility of S. aureus to Vancomycin and Gentamycin to be as high as 91.7%. Similarly, Rijal, et al.  reported 96.9% susceptibility of S. aureus isolates to Vancomycin.
The intensive use of the antibiotics in the study area could account for the possible isolation of hospital type MRSA in the community that have developed resistance to many types of antibiotics and also indicates the transfer of these resistant genes to the microbial community outside the hospital. The resistances of MRSA to non β-lactam antibiotics were the characteristics of HA-MRSA . With this regards, our result shows the mixing of HA-MRSA and CA-MRSA in the community. Several researchers [27, 29] identified the possible mixing of HA-MRSA and CA-MRSA. Likewise, Klevens et al.  also reported the mixing of CA-MRSA with HA-MRSA in intensive care unit patients after studying MRSA rates and trends between 1992 and 2003, the result that showed the rise in HA-MRSA from 35.9% to 64.4%. The same authors also showed a significant decrease in MRSA resistance to non-β-lactam antibiotics including Gentamycin, Tetracycline and Trimethoprim-sulfamethoxazole and significant increase in MRSA infection. This indicates that HA-MRSA is also responsible for increase in prevalence of CA-MRSA because of significantly related risk factors. The risk factors investigated in our present work are responsible for high rate of transmission of HA-MRSA from Hospital to the community in Jimma town.
In general, the present study revealed high CA-MRSA both among primary school children and inmates in jail of Jimma zone, calling for appropriate surveillance for drug resistance patterns of microbial isolates for commonly used antibiotics not only within the health institutions, but also the community at large.