Prevalence of Bacterial Ocular Infections among Patients Attending Eye Clinic of Aminu Kano Teaching Hospital and Murtala Muhammad Specialist Hospital, Kano

Abstract

The eye, a functionally and structurally complex organ, experiences a variety of bacterial, viral, fungal and parasitic infections. Bacteria are major causative agents of eye infections that can lead to loss of vision. The objective of this study was to determine the bacterial etiologic agents associated with ocular infections, antimicrobial susceptibility pattern of incriminated isolates and associated factors among patients who visited the eye unit of Aminu Kano Teaching Hospital (AKTH) and Murtala Muhammad Specialist Hospital (MMSH). A hospital-based cross-sectional study was conducted at MMSH and AKTH from 25 May 2021 to 20 July 2021. Specimens from the ocular areas were collected from a total of 88 patients who visited the eye unit. Specimens were inoculated on blood agar, chocolate agar, MacConkey agar and mannitol salt agar. Isolated bacteria were identified by a series of biochemical tests using the standard bacteriological method. Antimicrobial susceptibility test was performed according to the Clinical and Laboratory Standard Institute by disk diffusion method. Factors that could be associated with ocular infection were collected by using structured questionnaire. Data analysis was done using SPSS version 16.0 software package. A P value less than 0.05 was considered statistically significant. Out of the total 88 study participants with ocular infections, 78 (88.6%) were culture-positive. The proportions of Gram-positive and Gram-negative bacteria were 28 (31.8%) and 60 (68.2%), respectively. Among Gram-positive bacteria, Staphylococcus aureus were predominant. Among Gram-negative bacteria, Heamophillus influenzae were predominant. Most of the isolates were susceptible to ofloxacin and resistant to amoxicillin-clavulanic acid. Majority of ocular infections in this study were caused by bacteria; Gram-negative bacteria were responsible for most cases.

1. Introduction

The eye, a functionally and structurally complex organ, experiences a variety of bacterial, viral, fungal and parasitic infections [1]. Bacterial infections are the major contributors of ocular infections worldwide. Infection can be mono or poly-microbial and is associated with many factors including contact lenses, trauma, surgery, age, dry eye state, chronic nasolacrimal duct obstruction and previous ocular infections [2].

Staphylococci are the leading ocular isolates worldwide among the Gram-positive bacteria [3]. Whereas Pseudomonas aeruginosa, Klebsiella pneumoniae and Escherichia coli are the major Gram-negative bacteria isolated from ocular Infections [4]. The eye may be infected from external sources or through intraocular invasion of microorganisms that are carried out by blood stream [5]. External bacterial infections of the eye are usually localized but may frequently spread to other tissues.

Infection of the eye leads to conjunctivitis, keratitis, blepharitis, dacryocystitis, endophthalmitis and other infections which are responsible for increased incidence of morbidity and blindness worldwide [6].

Ocular infections, if left untreated, can damage the structure of the eye leading to visual impairment and blindness. Even though the eye is rigid and protected by continuous flow of tear which contains antibacterial substances, inflammation and scarring once occurred may not be easily resolved and required immediate management [7].

Ocular infection is a life-threatening condition which needs early diagnosis and treatment to save the patients’ eye. In Africa alone, between 1000 and 4000 children are blinded annually by conjunctivitis [8]. Ocular infections are the second most common cause for blindness in developing countries [9].

Ocular infections are common in north-western states in Nigeria. In view of the changing etiological agents documented in other parts of the world and evolving resistance of infective agents to therapeutic agents, which may increase the risk of treatment failure with potentially serious consequences [10]. Therefore, up-to-date information is essential for appropriate antimicrobial therapy and management of ocular infections [11].

The objective of the study to determine the prevalence of bacterial ocular infections, the bacterial etiologic agents associated with ocular infections, the bacterial isolates in patients according to age, sex and other demographic factors and to investigate the antimicrobial susceptibility pattern of incriminated isolates among patients attending eye clinic of Aminu Kano teaching hospital and Murtala Muhammad specialist hospital.

2. Materials and methods

2.1 Sample collection and bacterial identification

A prospective cross-sectional study was conducted at Aminu Kano Teaching Hospital, which is a tertiary hospital situated in Kano state, Nigeria, and Murtala Muhammad Specialist Hospital, a secondary healthcare institution and as well a referral centre for a number of primary healthcare centres, also situated in Kano state. Socio-demographic data collection and relevant clinical evaluations of 88 patients with bacterial ocular infections were done using structured questionnaire. The bacterial ocular infections were clinically defined after patients were examined by an ophthalmologist.

The specimens were collected from eyelids and conjunctiva using sterile cotton swab moistened with sterile saline. The swab was rolled over the eyelid margin from medial to the lateral side and back again. Pus from lacrimal sac (dacryocystitis) and blepharitis was collected using dry sterile cotton-tipped swab either by applying pressure over the lacrimal sac to allow purulent material to reflux punctum or by irrigating the lacrimal drainage system [12]. The swabs were then transported immediately to the laboratory.

Bacterial identifications from eye discharge specimens were performed using standard procedures. Direct gram staining was done for all specimens. The specimens were inoculated on a proper culture media; MacConkey agar, Mannitol Salt Agar, Blood agar and Chocolate agar (Oxoid Ltd. Basingstoke, Hampshire, UK). The inoculated plates was incubated for 24 hours at 37°C. The aerobic atmospheric condition was maintained for the MacConkey agar and mannitol salt agar, while the chocolate agar and blood agar were incubated at 5–10% CO₂ atmosphere.

All the plates were initially examined for growth after 24 hours. After getting pure colonies, further identification was conducted using standard microbiological techniques, which include Gram stain, colony morphology and biochemical tests, namely lactose fermentation, mannitol fermentation catalase, coagulase, oxidase and indole tests.

2.2 Susceptibility testing

Once pure culture was obtained, a loopful of bacteria was taken from colony and transferred to a tube containing 5 ml of physiological saline and mixed gently. The suspension was incubated at 37°C until the turbidity of the suspension becomes adjusted to 0.5 McFarland standards. The suspension was uniformly rapped on to Mueller-Hinton agar for non-fastidious organisms and Mueller-Hinton agar with defibrinated sterile sheep blood (10% V/V) for fastidious organisms. Antimicrobial susceptibility test was carried out on each identified bacterium using the Kirby-Bauer disk diffusion method on Muller Hinton agar (Oxoid Ltd. Basingstoke, Hampshire, UK) based on clinical and laboratory standard institute (CLSI) 2014 guideline. Identifications and antibiotic sensitivity tests were performed according to the manufacturer’s instructions. The antimicrobials used include the following: ceftazidime (30 μg), cefuroxime (30 μg), erythromycin (15 μg), cefixime (5 μg), gentamicin (10 μg), ciprofloxacin (5 μg), amoxicillin-clavulanic acid (30 μg), nitrofurantoin (300 μg), ceftriaxone (30 μg), oflaxocin (5 μg) and cloxacillin (10 μg) (Oxoid, England). Reference strains of E. coli ATCC 25922 and Staphylococcus aureus ATCC 25923 were used as quality control measure for identification criteria and antimicrobial susceptibility tests.

2.3 Quality control

Prior to actual data collection comprehensiveness, reliability and validity of questionnaires were pre-tested on 10 patients at AKTH and MMSH. All specimens were collected following standard operating procedure for ophthalmic specimen collection. The sterility of culture media was ensured by incubating 5% of each batch of the prepared media at 37°C for 24 hours. Performances of all prepared media were also checked by inoculating standard strains such as E. coli (ATCC 25922), S. aureus (ATCC 25923) and P. aeruginosa (ATCC 27853) obtained from AKTH (Ramesh et al., 2010). The qualities of biochemical testing procedures were checked by these reference strains.

2.4 Statistical analysis

The data analysis was done using IBM SPSS software package version 16.0. The results obtained were analyzed using Descriptive Statistics, that is, frequency and percentages. Categorical variables were analyzed using Chi Square test. Finally, the results were presented in tables and figure.

3. Result

The study was conducted in Aminu Kano Teaching Hospital and Murtala Muhammad Specialist Hospital Kano with a total of 88 participants. All participants were examined for bacterial ocular infection. This chapter brings the summary of the study details of bacterial ocular infection and, the result are summarized in tables and figures as follows.

3.1 Prevalence of bacterial ocular infections among ocular infection patients

The prevalence of bacterial ocular infection is shown in Figure 1. Out of the 88 study participant who were examined for ocular infection, 78 (88.6%) were culture-positive and 10 (11.4%) have no growth.

Figure 1.

Prevalence of bacterial ocular infection (n = 78).

3.2 Bacterial etiology of ocular infections

Among the total bacteria isolated, 28 (31.8%) and 61 (68.1%) were Gram-positive and Gram-negative bacteria, respectively. Mixed infection was found in 10 participants (11.3%). H. influenza (29.5%) was the predominant bacteria (Tables 1 and 2). The predominant bacterium among almost all clinical presentation was S. aureus (27.3%) except for conjunctivitis where the predominant bacteria were H. infleunza and S. aureus (Table 3).

Agent	Frequency (n)	Percentage (%)
S. aureus	24	27.3
S. pneumoniae	4	4.5
H. influenzae	26	29.5
P aeruginosa	23	26.1
K. pneumoniae	7	8.0
E. coli	4	4.5
Total	88	100

Table 1.

Bacterial etiologic agents associated with ocular infections.

n = frequency, % = percentage.

Antibiotic	Concentration(μg)	Susceptible n (%)	Intermidiate n (%)	Resistant n (%)
Ceftazidime	30	0	0	26 (100)
Cefuroxime	30	10 (38.5)	0	16 (61.5)
Gentamicin	10	0	1 (4)	25 (96)
Cefixime	5	2 (7.7)	2 (7.7)	22 (84.6)
Nitrofurantoin	300	0	0	26 (100)
Ciprofloxacin	5	19 (73)	1 (4)	6 (23)
Ofloxacin	5	24 (92.3)	0	2 (7.7)
Amoxicillin-clavulanic acid	30	1 (4)	0	25 (96)

Table 2.

Antimicrobial susceptibility pattern of H. influenzae (n = 26).

Variables	S. aureus n (%)	S. pneumoniae n (%)	H influenzae n (%)	P aeruginosa n (%)	K pneumoniae n (%)	E coli n (%)	P value
Previous infection
Yes	3 (3.4)	0	2 (2.3)	4 (4.5)	1 (1.1)	0	0.897
No	21(23.9)	4 (4.5)	22 (25)	19 (21.6)	6	4 (4.5)
Clinical presentation
Conjunctivitis	20 (22.7)	4 (4.5)	25 (28.4)	22 (25)	7 (7.9)	4 (4.5)	0.745
Darcryocytitis	2 (2.3)	0	1 (1.1)	0	0	0
Blephritis	2 (2.3)	0	0	1 (1.1)	0	0
Immune status
Immunocompromised	2 (2.5)	0	0	0	0	0	0.363
Non immunocompromised	22 (25)	4 (4.5)	26 (29.5)	23 (26.1)	7 (7.9)	4(4.5)

Table 3.

Distribution of bacterial isolates in patients based on clinical data (N = 88).

KEY: % = Percentage, significance level = P < 0.005.

3.3 Antimicrobial susceptibility profile

From 28 Gram-positive bacteria isolated, 20 (71.4%) and 16 (57.1%) were susceptible to ceftriaxone and ofloxacin, respectively. Among 24 S. aureus, 22 (91.6%),21 (87.5%) and 20 (83.3%) were resistant to augmentin, erythromycin and gentamicin, respectively (Table 4). All Streptococcus pneumoniae isolates were susceptible to erythromycin (Table 5). Among 60 Gram-negative bacteria isolated, 50 (83.3%) and 55 (91.6%) were susceptible to ciprofloxacin and ofloxacin, respectively. Three-fourth (75%) of E. coli were susceptible to gentamicin (Table 6). 25/26 (96%), 2/4 (50%), 7/7 (100%) and 21/23 (91.3%) of H. influenza, E. coli, K. pneumoniae and P. aeruginosa were resistant to amoxicillin-clavulanic acid (augmentin) (Tables 2, 6–8).

Antibiotic	Concentration(μg)	Susceptible n (%)	Intermidiate n (%)	Resistant n (%)
Ceftazidime	30	0	1 (4.2)	23 (95.8)
Cefuroxime	30	1 (4.2)	0	23 (95.8)
Gentamicin	10	2 (8.3)	2 (8.3)	20 (83.3)
Ceftriazone	30	15 (62.5)	2 (8.3)	7 (29.2)
Erythromycin	15	2 (8.3)	1 (4.2)	21 (87.5)
Cloxacillin	10	0	2 (8.3)	22 (91.7)
Ofloxacin	5	13 (54.2)	1 (4.3)	10 (41.6)
Amoxicillin-clavulanic acid	30	0	2 (8.3)	22 (91.7)

Table 4.

Antimicrobial susceptibility pattern of S.aureus (N = 24).

Antibiotic	Concentration(μg)	Susceptible n (%)	Intermidiate n (%)	Resistant n (%)
Ceftazidime	30	0	0	4 (100)
Cefuroxime	30	1 (25)	0	3 (75)
Gentamicin	10	3 (75)	0	1 (25)
Ceftriazone	30	3 (75)	0	1 (25)
Erythromycin	15	4 (100)	0	0
Cloxacillin	10	1 (25)	0	3 (75)
Ofloxacin	5	2 (50)	0	2 (50)
Amoxicillin-clavulanic acid	30	0	0	4 (100)

Table 5.

Antimicrobial susceptibility pattern of S. pneumoniae (n = 4).

Antibiotic	Concentration(μg)	Susceptible n (%)	Intermidiate n (%)	Resistant n (%)
Ceftazidime	30	0	0	4 (100)
Cefuroxime	30	1 (25)	0	3 (75)
Gentamicin	10	3 (75)	0	1 (25)
Cefixime	5	0	0	4 (100)
Nitrofurantoin	300	0	1 (25)	3 (75)
Ciprofloxacin	5	4 (100)	0	0
Ofloxacin	5	2 (50)	0	2 (50)
Amoxicillin-clavulanic acid	30	1 (25)	1 (25)	2 (50)

Table 6.

Antimicrobial susceptibility pattern of E.coli (n = 4).

Antibiotic	Concentration(μg)	Susceptible n (%)	Intermidiate n (%)	Resistant n (%)
Ceftazidime	30	5 (21.7)	0	18 (78.3)
Cefuroxime	30	16 (69.6)	0	7 (30.4)
Gentamicin	10	5 (21.7)	1 (4.3)	17 (74)
Cefixime	5	0	0	23 (100)
Nitrofurantoin	300	3 (13)	0	20 (87)
Ciprofloxacin	5	19 (82.6)	1 (4.3)	3 (13)
Ofloxacin	5	22 (95.7)	1 (4.3)	0
Amoxicillin-clavulanic acid	30	2 (8.7)	0	21 (91.3)

Table 7.

Antimicrobial susceptibility pattern of P. aeruginosa (n = 23).

Antibiotic	Concentration(μg)	Susceptible n (%)	Intermidiate n (%)	Resistant n (%)
Ceftazidime	30	5 (71.4)	0	2 (28.6)
Cefuroxime	30	2 (28.6)	2 (28.6)	3 (42.9)
Gentamicin	10	4 (57.1)	1 (14.3)	2 (28.6)
Cefixime	5	4 (57.1)	0	3 (42.9)
Nitrofurantoin	300	4 (57.1)	0	3 (42.9)
Ciprofloxacin	5	5 (71.4)	1 (14.3)	1 (14.3)
Ofloxacin	5	5 (71.4)	1 (14.3)	1 (14.3)
Amoxicillin-clavulanic acid	30	0	0	7 (100)

Table 8.

Antimicrobial susceptibility pattern of K.pneumoniae (n = 7).

3.4 Socio-demographic data

In the current study, a total of 88 patients seeking treatment for eye infection at AKTH and MMSH were included; there were no non-respondents. From the total study participants, 51 (58%), 29 (33%) and 61 (69.3%) were females, in 0–3 years age group and from rural areas, respectively. Most of the study participants were students and from hausa ethinic group 73 (83%) (Table 9).

Variables	Frequency (n)	Percentage (%)
Gender
Male	37	42
Female	51	58
Age group
0–3	29	33
4–11	16	18.2
12–17	5	5.7
18–39	21	23.9
> 40	17	19.3
Ethnic group
Hausa	73	83
Fulani	9	10.2
Youruba	3	3.4
Igbo	2	2.3
Others	1	1.1
Residency
Rural	61	69.3
Urban	27	30.7
Educational level
Primary	16	18.2
Secondary	21	23.9
Tertiary	8	9.1
Illiterate	11	12.5
Not applicable	32	36.4

Table 9.

Socio-demographic distribution of the study participants (N = 88).

n = frequency, % = percentage.

3.5 Clinical presentation

Among 88 study participants assessed, the proportions of clinical finding were as follows: conjunctivitis 82 (93.2%), dacryocystitis 4 (4.5%), blepharitis 2 (2.3%) (Table 10).

Clinical presentation	Frequency (n)	Percent (%)
conjuctivitis	82	93.2
dacryocystitis	4	4.5
blephritis	2	2.3
Total	88	100.0

Table 10.

Types of clinical presentations.

n = frequency, % = percentage.

3.6 Factors associated with ocular infection

None of the factors were significantly associated with ocular infections (P > 0.05). The proportions of bacterial eye infection among study participants with 0–3, 4–11, 12–17, 18–39 and ≥ 40 age groups in years were 29 (33%), 16 (18.2%), 5 (5.7%), 21 (23.9%) and 17 (19.3%), respectively. The proportions of bacteria eye infection in rural and urban area were 61 (69.3%) and 27 (30.7%), respectively (Table 11). The proportion of bacterial eye infection among participants with repeated infections was 10 (11.36%) and among non-repeated infection was 78 (88.6%). The proportions of bacterial eye infection among participants whom are illiterate, primary, secondary, tertiary and those that are yet to enter school were 11 (12.5%), 16 (18.2%), 21 (23.9%), 8 (9.1%) and 32 (36.4%), respectively (Table 11). Conjuctivitis is the predominant clinical presentation (Table 10). The proportion of bacterial eye infection among participants with risk of infection was 2 (2.3%) (Table 3).

Variables	S. aureus n (%)	S. pneumoniae n (%)	H influenzae n (%)	P aeruginosa n (%)	K pneumoniae n (%)	E coli n (%)	P value
Gender
Male	12 (13.6)	2 (2.3)	9 (10.2)	11 (12.5)	2 (2.3)	1 (1.1)	0.757
Female	12 (13.6)	2 (2.3)	17 (19.3)	12 (13.6)	5 (5.7)	3 (3.4)
Age group
0–3	9 (10.2)	0	7 (7.9)	7 (7.9)	3 (3.4)	3 (3.4)	0.411
4–11	4 (4.5)	1 (1.1)	4 (4.4)	5 (5.7)	2 (2.3)	0
12–17	2 (2.3)	0	2 (2.3)	0	1 (1.1)	0
18–39	3 (3.4)	3 (3.4)	6 (6.8)	8 (9.1)	1 (1.1)	0
> 40	6 (6.8)	0	7 (7.9)	3 (3.4)	0	1 (1.1)
Ethnic group
Hausa	19 (21.6)	3 (3.4)	20	21 (23.9)	7 (7.9)	3 (3.4)	0.946
Fulani	3 (3.4)	1 (1.1)	3 (3.4)	1 (1.1)	0	1 (1.1)
Yoruba	2 (2.3)	0	1 (1.1)	0	0	0
Igbo	0	0	1 (1.1)	0	0	0
Others	0	0	1 (1.1)	0	0	0
Residency
Rural	16 (18.2%)	2 (2.3%)	17 (19.3%)	19 (21.6)	5 (5.7)	2 (2.3)	0.609
Urban	8 (9.1%)	2 (2.3%)	9 (10.2%)	4 (4.5)	2 (2.3)	2 (2.3)
Educational level
Primary	4 (4.5)	1 (1.1)	5 (5.7)	3 (3.4)	3 (3.4)	0	0.228
Secondary	3 (3.4)	1 (1.1)	10 (11.4)	5 (5.7)	1 (1.1)	1 (1.1)
Tertiary	3 (3.4)	2 (2.3)	1 (1.1)	2 (2.3)	0	0
Illiterate	5 (5.7)	0	3 (3.4)	3 (3.4)	0	0
Not apllicable	9 (10.2)	0	7 (7.9)	10 (11.4)	3 (3.4)	3 (3.4)

Table 11.

Distribution of bacterial isolates in patients based on age gender and other socio-demographic data (N = 88).

KEY: % = Percentage, significance level = P < 0.005.

4. Discussion

The prevalence of culture-positive ocular infections caused by bacteria found in this study was 88.6%, and the result is comparable with other previous study reports conducted in India (88%) [13] and Egypt (87.8%) [14]. Our finding is high compared with the report from Southern Ethiopia (74.7%) [15], Bangalore (34.5%) [16], Gondar (47.4%) [17] and Addis Ababa (54.9%) [18]. The difference can be attributed to geographic location, study period, study population, sanitary condition and laboratory method used. Gram-negative bacteria were predominant in our study unlike report from other countries [19]. In the current study, the predominant bacterial isolates were H. influenzae (29.5%) followed by S. aureus (27.3%). The finding of this study is not comparable with previous studies conducted in Ethiopia [20], Nigeria [21] and India. The proportion of Gram-negative bacteria isolated, (31.8%) in this study is high compared with the report from Ethiopia [22]. Among Gram-negative bacteria isolated in the present study, H. influenzae (29.5%) was the most prevalent followed by P. aeruginosa (26.1%), K. pneumoniae (8%) and E. coli (4.5%).

Conjunctivitis was the dominant type of clinical presentation (93.2%) observed in this study followed by dacryocystitis (4.5%) and blepharitis (2.3%). In this study, the majority of bacteria were resistant to ceftazidime and cloxacillin, while most of them were susceptible to ofloxacin. This finding is in agreement with the study conducted in Gondar, Ethiopia [17], Jimma, Ethiopia [23] and Uganda [24]. The reason for increased resistance to ceftazidime and cloxacillin may be prior exposure of the isolates to these antibiotics. Moreover, these antibiotics are common, and patients can access them easily with low price and often can be purchased without prescription over the counter in different pharmacies [16]. Most of the S. aureus were resistant to ceftazidime (95.8%) and cloxacillin (91.7%); however, 70.8% were susceptible to ceftriaxone. A similar finding was reported from other parts of Ethiopia [18]. However, low susceptibility (87.5%) to gentamicin was reported from other parts of Ethiopia [22]. Like S. aureus, S. pneumoniae (75%) were resistant to cloxacillin; similarly high resistance to penicillin was reported from Ethiopia [20]. S. pneumoniae isolated in this study were susceptible to erythromycin and gentamicin; this is not in line with other studies [22], in contrast to another study from Ethiopia [20].

H. influenzae and P. aeroginosa isolates in this study were susceptible to ciprofloxacin, ofloxacin and were resistant to gentamicin, nitrofurantoin and amoxicillin-clavulanic acid. E. coli isolates in this study were susceptible to ciprofloxacin, ofloxacin and gentamicin and were resistant to amoxicillin-clavulanic acid, ceftazidime and cefuroxime. K. pneumoniae isolates in this study were susceptible to ciprofloxacin, ofloxacin and ceftazidime. All of them were resistant to amoxicillin-clavulanic acid; this is in partial agreement with the Getahun et al. report.

In the present study, the sensitivity to antibiotics was variable in bacterial ocular infections and increased resistance to most antibiotics. The fluoroquinolones (ciprofloxacin and ofloxacin) were highly effective against all bacterial isolates, followed by ceftriaxone.

In conclusion, in the current study, the most prevalent clinical presentation was conjunctivitis followed by dacryocystitis. From 88 study participants with ocular infections, 88.6% were culture-positive. Gram-negative bacteria were the most prevalent with H. influenzae taking the largest share. Most of the isolates are susceptible to ofloxacin and resistant to amoxicillin-clavulanic acid. And none of the factors were significantly associated with ocular infections (P > 0.05).

The following recommendations are made based on the findings of the study: To mitigate the burden of bacterial ocular infections, physicians should regard risk reduction and comply with etiologic approach of diagnosis. Antibiotic resistance among ocular pathogens is a challenge to the ophthalmologists. Resistance to most groups of antibiotics is increasing with resultant decline in the effectiveness of many commonly used topical antibiotics. It remains to be seen whether newer antibiotics such as besifloxacin will outlive the others before it, especially because of lack of systemic use. A strategy including judicious use of antibiotics in humans, animals and agriculture fields along with development of new products having low-resistance potential is required to end or at least reign in the current trend. Health education and personal hygiene should be practiced, and additional studies are needed in this study area.

4.1 Limitation of the study

The limitation of the study was that the lack of reagents limited the diagnosis of Chlamydia infections.

Acknowledgments

All thanks and Honors go to Almighty Allah (S.W.T) for my health, strength and guidance throughout this period.

I wish to express my profound gratitude to the supervisor of this work, Professor Abdulhadi Sale Kumurya of the Department of Medical Laboratory Science, Bayero University, Kano, for his due contributions, fatherly advices and assistance towards the completion of this research project.

My earnest appreciation to all lecturers of the Department of Medical Laboratory Science, Bayero University, Kano, headed by my respected Head of Department Dr. Jamilu Abubakar Bala. Special thanks to the staff of Medical bacteriology Unit of the Medical Laboratory Science Department, Bayero University, Kano. And also my special gratitude goes to my mentor, Malama Rahinatu S. Sharfadi.

My sincere gratitude also goes to all members of staff of the Department of Medical Microbiology, Aminu Kano Teaching Hospital, Kano, and everybody who contributed in one way or the other to the completion of this project.

With much and sincere humility, my deepest gratitude goes to my beloved parents Haj. Afiya bashir and Alh Abdulaziz Lawan, my aunties and uncles especially Alh Abdulhadi Lawan, Kawu Aminu, Kawu Mahdi, aunty Binta and aunty Sadiya as well as to my relatives and friends for their continuous moral support and encouragement, and also my sincere appreciation goes to my father’s best friend who has also been a great father to me Dr. Auwal Baba Ahmad and to my sarang Sauban M. Jibril. I would also like to thank my quadruple squad Bilkisu B., Maryam B and Rukkayya M. May Allah SWT reward you all with Jannatul Firdaus Ameen.

Lastly, I will be forever indebted to everybody who shared knowledge, a moment, classroom and laboratory with me during my undergraduate programme.

Additional information

This study replicates the original research reported in: Mohammed AA, Ali MM, Zenebe MH. Bacterial etiology of ocular and periocular infections, antimicrobial susceptibility profile and associated factors among patients attending eye unit of Shashemene comprehensive specialized hospital, Shashemene, Ethiopia [Internet]. Vol. 20, BMC Ophthalmology. Springer Science and Business Media LLC; 2020. Available from: http://dx.doi.org/10.1186/s12886-020-01398-w.

Abbreviation

AKTH	Aminu Kano Teaching Hospital
MMSH	Murtala Muhammad Specialist Hospital