O r i g i n a l A r t i c l e Singapore Med J 2009; 50 (2) : 208 Antibiotic susceptibility pattern of Staphylococcus species isolated from telephone receivers Smith S I, Opere B, Goodluck H T, Akindolire O T, Folaranmi A, Odekeye O M, Omonigbehin E A ABSTRACT prevent the spread of infectious diseases through Introduction: Microorganisms are transferred the use of public telephones. to everyday objects from the environment and infected individuals. Pathogenic microbes are Keywords: antibiotic resistance, antimicrobial transmissible from the air, skin, hands and other susceptibility pattern, Staphylococcus aureus, interpersonal contacts and cause diseases most telephone receivers of the time. This study centres on the microbial Singapore Med J 2009; 50(2): 208-211 assessment of telephone receivers, their ability to transfer bacterial infections and the isolation INTRODUCTION of these microorganisms from receivers, with Microorganisms are ubiquitous, and a mixture of an emphasis on Staphylococcus aureus and its microbes are often transferred to everyday objects from antibiotic susceptibility pattern.
the environment and infected individuals. Pathogenic
microbes are transmissible via air, skin, food, water and
Methods:1,591 isolates were obtained from other interpersonal contacts, and in most cases, they roadside telephone booths in 16 different cause diseases and infections. Transmission of these Molecular Biology and locations in the Lagos metropolis. They were all
infectious agents typically involves their escape from the
Biotechnology Division, characterised using the Cowan and Steel’s manual, Nigerian Institute of
host and entry into a new host.(1,2) These organisms can
Medical Research, after which the antimicrobial susceptibility also be transmitted through the sharing of instruments PMB 2013, Yaba, pattern of the most frequently-occurring isolate and materials, such as bedding and telephones. The Lagos, Nigeria was determined.
telephone system, for example, is an instrument or system
used in sending sounds and messages across a distance
Results: Of all the locations, Oshodi was found through a cable. It is a device used for the conversion of to have the largest number of microorganisms, sound into an electrical impulse that is converted back with Akoka having the least. The organisms were
into sound at the receiving end, and has to a large extent
Providencia, Klebsiella, Citrobacter, Enterobacter, promoted the transmission of pathogenic microbes. Due Proteus, Escherichia, Staphylococcus, Bacillus, to the importance of communication, people now use Streptococcus, Micrococcus and yeast . telephones everywhere and in all areas of life, such as in Department of Botany, Staphylococcus spp. was the most frequently Lagos State University,
their homes, offices, schools, churches, mosques, hotels
Lasu Ojo, occurring, making up 20.2 percent of the total and hospitals, and it is used by both the healthy and the Lagos, Nigeria number of isolated organisms, followed by Bacillus sick.(3) During usage, bacterial agents can be transferred (18 percent), while Enterobacter and Citrobacter from an infected individual or an asymptomatic carrier were the least common. 44 percent of the total of a microorganism to the surface of telephones through Staphylococcus screened for an antimicrobial either direct contact with parts of the body, such as the susceptibility pattern showed high resistance to mouth, ear and skin, or by indirect contact with aerosols, most of the antibiotics used.
saliva droplets and infectious particles, to other users of
Conclusion: This result could be related to the
Organisms from the normal flora can be transmitted
Correspondence to: emergence of Staphylococcus-resistant strains, onto phone receivers via sneezing or coughing. The
Dr Stella Ifeanyi Smith especially in a highly-populated area where there proliferation of bacteria in the mouth is due to the
Tel: (234) 80 3705 8989 Fax: (234) 1 342 6171 are health and hygiene problems and where presence of food particles in the mouth, which can be drugs are abused. Precautions should be taken to passed onto the telephone receiver when talking as Singapore Med J 2009; 50 (2) : 209 Table I. Distribution of organisms isolated from Table II. Antimicrobial susceptibility patterns of telephone receivers. Staphylococcus aureus strains isolated.
rents that are affordable for everyone even though they
lack good infrastructure and are poorly kept; whereas
droplet aerosol.(4) Direct contamination of the telephone
areas with better sanitation and good infrastructure are
receiver by microorganisms from the hand, throat and
sparsely populated because of the high rent. Regardless
skin of users also occurs.(5) The microorganisms are
of the area, however, all have telephone booths that
continuously disseminated from the mouth and the
are accessible to the public. The aim of this study was
nasal cavity when someone sneezes, coughs, laughs,
to isolate bacterial agents that can be transmitted by
talks and breathes into the surrounding air and this can
telephone receivers and to screen Staphylococci (being
in turn be transmitted to susceptible healthy individuals
the most commonly-isolated microorganism) for their
by way of the respiratory tract. The microorganisms are
antimicrobial susceptibility patterns.
well adapted to transmission by way of nasopharyngeal
secretions and saliva droplets and are highly resistant to
drying and desiccation, thus their easy movement from
500 swabs were collected from roadside telephone
one host to another.(6) Telephone boxes located in hostels,
booths in 16 different locations in the Lagos metropolis.
lobbies, corporate offices and public centres are possible
The locations were selected randomly from all the
transmitters of these pathogenic microbes. Some of the
local government areas in the state. All the swabs were
known normal flora sometimes cause diseases when the collected with aseptically-moistened swab sticks using
tissue defences of the host are lowered, e.g., Staphylococci
normal saline solution and transported to the laboratory
can be carried frequently from the nose and moistened
in coolers containing ice packs. The swabs were then
areas of the skin, where they do not cause diseases, but
streaked onto blood agar and MacConkey agar plates and
when they land on other parts of the body, they may cause incubated at 37°C for 18–24 hours. Microscopy and Gram
diseases or infections especially in immunosuppressed
staining were carried out on the isolated organisms for
presumptive identification, after which the isolates were
The direct dissemination of bacteria from people is
characterised according to Cowan and Steel’s manual.(7)
of particular importance in the assessment of telephones
Antimicrobial susceptibility tests were carried out using
for the presence of microorganisms. Bacteria can be
the disc diffusion method of Clinical and Laboratory
liberated from human beings through three principal
Standards Institute.(8) The most frequently-occurring
means, viz. activities involving the respiratory tract, such
organism was inoculated and streaked aseptically on
as sneezing, coughing, talking, laughing; movements that
Muller-Hinton agar plates, after which the antibiotic discs
shed bacteria-bearing particles from the body, skin wound were placed on them and incubated at 37°C for 18–24
or discharge from body lesions; and re-dissemination of
hours. The plates were observed after 24 hours for culture
organism-bearing particles from dust in phone booths,
streets and sidewalks. In Lagos, however, one of the
major means of communication is by telephone, and
the government has placed several telephone booths in
Out of 500 swabs collected from different public telephone
strategic areas of the state. Every local government has at centres in the Lagos metropolis, 1,591 organisms were
least two booths, depending on how large and populated
isolated. Samples collected from Oshodi were found
the area is. Most densely populated areas have cheaper
to have the highest number of isolates, while samples
Singapore Med J 2009; 50 (2) : 210
collected from Akoka had the least number of isolates. Of
all the isolates, Staphylococcus spp. was most frequently
The isolation of S. aureus was closely followed by
isolated (20.2%) from all 16 locations, followed by
Bacillus subtilis, which is known to be free-living in the
Bacillus, (18.0%), and the least occurring organism was
soil, atmosphere and water.(11) The presence of the BacillusEnterobacter spp. (1.3%). (Table I). Table II shows the
spp. on the telephone may be a result of the unhygienic
antibiotic susceptibility patterns of 27 Staphylococcus
handling of the telephone receiver. Streptococcus aureus (S. aureus) isolated and identified by tube catalase
pneumoniae found in the oral and nasal passages was
test, out of which 12 (44%) were resistant to oxacillin.
also isolated. Infections that are caused by it include
pneumonia, meningitis, endocarditis, otitis, bronchitis,
DISCUSSION
bacteraemia and sinusitis.(12) Other organisms isolated
It was noticed from this study that the frequency of
include Micrococcus spp. which causes micrococcal
isolation of the bacterial agents vary with location and
infections associated with that of Staphylococcus spp.
species. Oshodi was found to have the highest number of
e.g. abscess. Some yeast or yeast-like organisms are
microorganisms, with Akoka having the lowest number
parasites for people, e.g. Candida albicans, which
of isolates. This can be explained by the fact that Oshodi
generally produces an ulcerative condition of the mouth
is a densely-populated area with a high level of activity.
and throat, and may later be localised in some internal
It is also a market place with debris, waste materials,
organs and produce infections. However, a previous
perishable food items and diseased individuals all over
report by O’Connor et al showed the lack of occurrence
its environs, and hence Oshodi is highly polluted, with
of methicillin-resistant S. aureus (MRSA) on municipal
a high presence of airborne microorganisms that could
settle on the telephone. On the other hand, Akoka,
The susceptibility patterns shown in this study
which is sparsely populated, has less activities within its
suggest that it is absolutely necessary to obtain sensitivity
environment and therefore a lower level of pollution.
reports before the initiation of antibiotic therapy in
The occurrence of Staphylococcus spp. was also the
suspected MRSA patients. It should also be noted that
highest among all the isolated organisms, with S. aureus
antibiotic sensitivity testing is only a guide and that
making up 8.4% (27) of the total. This high occurrence
conditions in vivo may be different from those obtained
may be due to its resistance to drying which favours its
in vitro. The ultimate decision to utilise a particular
transmission and its presence as part of the normal flora of
antibiotic depends on such factors as toxicity, costs and
the nose, mouth and skin. Its transmission from one host
serum attainable levels. This study agrees with other
to another susceptible host is known to be responsible
studies that MRSA, besides having established itself as
for epidemic pyogenic infections in hospitals as well
a major hospital pathogen, is now beginning to prevail
as epidemic diseases. However, this study agrees with
in a wider community.(14) The emergence of MRSA in
earlier work conducted by other researchers who reported
the community is a major public health threat because
that S. aureus makes up about 20% of the microbial
these strains are resistant to B-lactam antibiotics, which
load in the air. They also reported that the organism is
are used empirically to treat a variety of infections,
constantly disseminated from the nasal cavity during
including pneumonia.(15,16) The result of this study is
talking, breathing and even exercising.(9) 44% of the
worrying because most resistant strains were isolated
total number of strains screened for antimicrobial
from areas with isolated risk factors, such as health and
susceptibility patterns showed strong resistance to most
hygiene problems, sharing of contaminated items, having
of the antibiotics used. This may be associated with the
active diseases and crowded living conditions. Most of
practice of self-medication and the indiscriminate use of
the transmission therefore appears to be from people with
antibiotics, which has led to S. aureus becoming resistant
to relatively safe antibiotics. It is noteworthy that this
In conclusion, it can be established that the number
organism is present in all the samples. It is known to be a
of microorganisms that are constantly present on public
normal component of humans’ indigenous microflora and
telephone receivers depends on the frequency of usage
is carried asymptomatically in/on a number of body sites.
and location of each particular telephone. The telephone
Its transmission from these sites causes both endemic and could be a very good source of infectious diseases.
epidemic diseases.(10) Thus, staphylococcal infection can
Further studies should be carried out to determine the rate
be transmitted by the holding of telephones contaminated
of infection through the use of public telephones. Singapore Med J 2009; 50 (2) : 211 REFERENCES
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Using the Cornell late blight simulator to test biological questions: a case study on the influence of the source of irrigation water on Phytophthora infestans development O Frenkel1, D Shtienberg1 and U Yirmiyahu2 Computer simulation models, if properly validated, can be used as research tools. The models can be used for testing biological hypotheses by conducting simulation experim