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Cross contamination is defined as the physical movement or transfer of harmful bacteria from one person, thing, or place to another. It is a major factor in food poisoning, and has four common sources: food, people, equipment, and work surfaces (Reynolds et al., 2005).

Stephen Aban and Kwaku Tanu Debra in their study indicated the ability of food-borne pathogens to contaminate fingers from metal keyboards in ATMs, where a contaminated finger was used to touch the surface of a feeder agar plate, at several points to transfer contaminants from the switches. Then another disinfected finger of your choice was used to touch the surface of another nutrient agar plate classified as a control (Abban & Tano, 2011).
            In crowded ATMs, the number of bacteria and fungi was increased, whereas in non-crowded ATMs the level was inconsistent and indicated to be lower (Mabel et al., 2014). In addition, (Oluduro et al., 2011) reported that ATM keyboards contain more bacteria than computer keyboards and this may be because ATMs are usually out in the open and exposed to wind and rain. However, this is not very accurate as there are two types of ATMs across Sakaka city; it is possible to drive through the machines and ATM rooms. In this study, samples were taken from both engines through an in-room ATM machine. As a result, differences are expected as the temperature, humidity and exposure to sunlight differ between the two types of ATMs. This study aimed to determine the bacterial contamination of the keyboards and screens of automatic teller machines, to identify the pathogenic bacterial species that can be transmitted through the ATMs and to compare the degree and type of contamination between the payment machines through the rooms of the ATMs.

MATERIALS AND METHODS

Sample collection
Samples collection were performed using sterile cotton swabs moistened with sterile normal saline then used to swap ATM’s keyboard and touch screens then transferred to screw-cap tubes that contain sterile normal saline to prevent dryness. Samples were transferred and processed immediately in the laboratory within one hour of collection.
Isolation of bacteria
Each sample were inoculated on both Blood Agar and MacConkey Agar culture media. Culture were performed in Lawn method under aseptic condition then plates were incubated at 37⁰C under aerobic condition for 24-48 hrs. After that, colonies with significant growth were selected for further isolation. According to the manufacturer instruction, the purified isolates were processed after confirmation of Gram nature by the automated microbiology system –Micro Scan WalkAway-96 plus, Siemens Healthcare Diagnostics- Germany.
Statistical analysis
The numerical data were collected and computerized using SPSS program version 16, 2007. The description of the data was done in the form of frequencies and percentages for normally distributed quantitative data. The analysis of data was done to test statistical significant differences between groups by Independent sample t- test; to compare between two groups. One Way ANOVA test was used to compare between more than two groups by Post Hoc test LSD (Least significant difference) to compare intergroup.

RESULTS AND DISCUSSION

This study identified some most microorganisms on the surface of ATMs. Overall, spore forming aerobic Bacillus spp. was predominant isolates. This confirms the ubiquitous nature of these bacteria giving it greater colonization ability as well as the ability of its spores to resist environmental changes, withstand dry, heat and certain chemical disinfectants for moderate periods (Tagoe & Kumi-Ansah, 2011). In addition, coagulase negative Staphylococcus appeared in almost all samples confirming results of (Mehmet, et al., 2013).

Table (1): Percentage of isolated bacteria from drive thru ATMs and ATM's rooms

 

Similar to (Anesa, et al., 2013) the commonest isolate of this study was S.epidermidis, a major component of normal flora on the skin, which probably explains its high prevalence as a contaminant. S.epidermidis can occasionally assume an opportunistic pathogenic role causing human infection such as endocarditis (Anastasiades et al., 2009). Of particular interest was the isolation of Staphylococcus aureus as it is linked to many human diseases. Many previous studies indicated S.aureus as a pathogen isolated from public sites (Zhang, et al., 2012) (Walkey et al., 2011) and (Seuli, et al., 2013). This may be attributed to their ability to show greater survival on hands (Gontijo, et al., 1985). In this study, S. aureus isolates showed resistance to 20% of tested antibiotics: Imipenem, Azithromycin, Rifampin and erythromycin.
            In this study, Enterobacter agglomerans, which is recognized as a plant pathogen, has been isolated from ATM near to institution of grain silos& flourmills. These opportunistic pathogens of animals and humans have been isolated from clinical specimens including blood, wounds, urine, throat, and internal organs. Hospital outbreaks has been recorded due to E. agglomerans contamination of anesthetic agent propofol, blood products, parenteral nutrition, and transference tubes used for intravenous hydration have been demonstrated (Mardaneh & Dallal, 2013). Likewise, and parallel to previous study of (Veerappan, et al., 2013), Vibrio damselae a pathogenic marine bacteria associated with wound infections in humans has been isolated near to a fish market (Belen, et al., 1992). Furthermore, ATMs from crowed areas such as markets showed increased degree of contamination. This is to be supported with the previous study of (Mabel et al., 2014).

           

The result of studying the gram nature of isolated bacteria indicated higher percentage of gram +ve compared to gram -ve spp. (66%) (34%) respectively. This result might be because most of skin commensals are gram +ve species (Oluduro et al., 2011). In addition, as the degree of hydration affects the survival of microorganism it is known that gram -ve bacteria are more sensitive to drying than  gram +ve one (Gontijo, et al., 1985) .In addition, the survival of gram +ve species on laminate surfaces is said to be greater than gram -ve organisms (Scott & Bloomfield, 2008).

           

Table (2): Percentage of Gram positive and Gram negative bacterial isolates from keyboards and screens of ATMs

           

 

A pioneering aspect has been a combined in this study to detect if there are any differences in the degree of contamination between drive thru and ATMs rooms. Because air conditionings reduces heat, keep moist inside rooms, and consequently favor the growth of bacteria, it was expected to find rooms more contaminated. Unexpectedly, both types of machines showed equal degree of contamination, (50%) for each. This could be a due to more frequent use of drive thru machines than rooms as it is easiest and more convenient to use making them suspected to contamination very frequent; overcoming heat and dry effects.

        

The pathogenicity also has been studied in both types of machines. In ATM's rooms, pathogenic bacteria comprise (12%) and opportunistic bacteria (80%). Whereas in drive thru machines, pathogenic bacteria was (24%) and opportunistic are (60%). Again, these results also may be attributed to more frequent use of drive thru machines making these machines more suspected to contamination and harboring of infectious agents.

        

Table (3): Pathogenicity of isolated bacteria isolated from drive thru machines

        

Table (4): Pathogenicity of isolated bacteria isolated from ATM's rooms

 

The result of this study showed that some antibiotics show a wide range of resistance, (60%) to mupirocin, (50%) to azithromycin, (40%) to erythromycin, (27.27%) to cefazolin, cefoxitin, cefuroxime, ertapenem & moxifloxacin and (20). %) For all: Amox / K Clav, Imipenem, and Oxacillin. E. coli bacteria isolated showed resistance to (30.4%) of tested antibiotics while E. aerogenes resistance to (34.7%) and (20%) by S. aureus. In general, Synercid, Teicoplanin, Tetracycline, Trimeth / Sulfa, and Vancomycin were the most effective antibiotics, while Mupirocin, Azithromycin, and Erythromycin were the least effective. It has been observed that the sensitivity of bacterial isolates to antibiotics is not static but dynamic and varies with time and environment (Hassan, 1995).

(6): Antibiotic sensitivity patterns for the isolated gram-positive bacteria.

 

CONCLUSION

This study ascertained that the screens and metallic keyboards of ATMs could act as vehicles of infectious diseases, therefore hand washing and good hygiene practice should be adopted before and after using of ATMs. Furthermore, ATMs screens and keyboards should be cleaned regularly with an appropriate disinfectant. All these precautions must be considered to reduce the population of microbes, which play an important role in diseases transmission.

REFERENCES

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