BACTERIAL PATHOGENS AND THEIR ANTIBIOTIC SUSCEPTIBILITY PATTERN IN IDOMA COMMUNITY, BENUE STATE OF NIGERIA [Original Research]
E.E. Okwori, S.I. Nwadioha, E.O.P. Nwokedi, M. Odimayo, G.T.A Jombo
Department of Medical Microbiology & Parasitology, College of Health Sciences, Benue State University, Nigeria
[emedpub – International Infectious Diseases Vol 1:5] [Date of Publication: 04.22.2011]
ISSN 2231-6019

April 22, 2011 at 11:29 AM

Abstract

Objectives: To isolate bacterial pathogens from a pool of clinical specimens in order to test their antibiotic resistance pattern.

Methods: A total of 20,000 samples were analysed in the laboratory between 1997 and 2000. The specimens were inoculated on the appropriate media for isolation of bacteria. Biochemical and serology tests were conducted to confirm the type of bacteria isolated. Antibiotic resistance test was also performed on each of the bacterial isolate, using the CLSI criteria.

Results: A total of 18,520 bacteria were isolated. The specimens were from nine different clinical sites, i.e from wound 22.8%, urine 31.7%, blood 12.4%, genital 7.7%, sputum 6.8%, stool 6.2%, aspirates 3.8% and ear/throat swabs 2.5%. Gram negative bacteria accounted for 76% of isolates. The main species were Pseudomonas 2238 (12.1%), Escherichia coli 2073 (11.2%), and Staphylococcus aureus 2511 (13.6%) of total isolates. Staphylococcus aureus showed resistance to penicillin (70%), ampicillin (65%) and cloxacillin (40%).  Escherichia coli was resistant to ampicillin (47%) and gentamicin (46%). Also, Salmonella typhi was resistant to chloramphenicol (49%) and Neisseria meningitides was resistant to penicillin (37%).

Conclusion: The rate of bacteria isolated from clinical specimens was high. The antibiotic resistance pattern will be useful for practicing clinicians in Nigeria.

Introduction:

Many diseases that were considered life threatening before World War II are now readily treated with antibiotics and other antimicrobials 1,2. Before the discovery of penicillin, which initiated the antibiotic era, the prognosis for people with infections diseases, such as bacterial pneumonia, tuberculosis and staphylococcal infections was grim 3. Physicians were able to identify the cause of diseases, but were generally unable to recommend treatment other than bed rest 4. Today antimicrobial drugs are widely prescribed. And simple cure for infections are provided. Unfortunately, the over use and misuse of these life-saving drugs, coupled with the bacterial world disability to adapt under selective pressure has led to an increase in the number of organisms that are resistant to the effects of antibiotics 5 . The increase in antibiotic resistance among a wide range of bacteria has caused some people to speculate that there is danger of seeing an end to the antibiotic era 5.

The success of antibiotic chemotherapy may often depend on the isolation and the determination of the susceptibility pattern of the causative organism. In developing country this practice is rare in most health institutions, due to the lack of facilities and personnel 6 . Multi-resistance of many bacteria to many antibiotics has been reported in the developing countries due to misuse of antibiotics 4,6. A way of combating the development of resistance is to control usage and formulation of antibiotic policy. The surveillance of the susceptibility patterns of the organisms prevalent in the individual hospital and community such as ours at Otukpo General Hospital will help to control resistance. Otukpo has attracted the attention of many interest groups both internationally and nationally since the advent of upsurge of HIV in the area. In addition, the study will help in the establishment of antibiotic policy in the area. The management can also be guided by the pattern of antibiotic susceptibility in the procurement of various antibiotics for the hospital. The physicians can also be guided in their choice of antibiotics in severe infections while waiting for the result of antibiotic sensitivity tests.

Patients and Methods:

Study Center: Otukpo General Hospital was chosen for the study. Otukpo is the traditional headquarter of Idoma people. It is located in North Central part of Nigeria; bounded by Enugu State in East, Cross River State on the West and Makurdi on the North, Kogi State on South.

The laboratory was equipped by the Department for International Development (DFID) a British governmental organization. DFID also obtained ethnical clearance from the Benue State Ministry of Health for this research project. For the purpose of the research those samples processed in the laboratory during three years of research (1997-2000) were processed free of charge for the patients. A retrospective analysis of the data was performed. Over 20,000 samples were received from patients attending outpatient clinics and in-patients facilities of the hospital.

Isolation and Identification of Bacteria:

Of 20,000 samples analysed, 18,520 isolates were obtained. Morphological appearance of colonies, biochemical tests and serology were used to identify these organisms. Enterobacteriacae were identified using standard biochemical reaction tests (table 1).

Table 1:Biochemical tests used for identifying the Enterobacteriacae

Non-lactose Fermenters Citrate agar
Urea agar
H2S-Kliger Iron agar
Motility-hanging drop
Mannitol Ornithine decarboxylase
Salmonella typhi -
Salmonella paratyphi A -
Salmonella paratyphi B -
Salmonella paratyphi C -
Shigella species - - - - -
Sh. dysenterive - - - - -
Sh. flexneri - - - -
Sh. Boydii - - - -
Sh. sonnei - - - -
Proteus sp. -
Pseudomonas sp. Oxidase positive

Final species identification of salmonella was based on serological tests. Commercially available kits were used for serotyping salmonellae by their O antigen A, B, C, C2, D and E (Copan Diagnostics, Corona, CA, USA).

Susceptibility Testing: The tests were performed using Muller-Hinton agar (Oxoid, Basingstoke, UK), supplemented with 5% sheep blood and chocolate agar. The inoculum of both test and control organisms were prepared from overnight growth and adjusted to a turbidity equivalent to 0.5 and 1McFarland opacity standard. The procedures were carried out according to standard recommendations 7. Antibiotic susceptibility tests were done against locally available antibiotics using disk diffusion method in accordance with the CLSI criteria Where other audiovisual festivals offer a wide range of already established audiovisual artists, buy-detox.com focuses on a new generation of artists and musicians, each with their own refreshing vision on audiovisual art and experience. (CLSI,2006) and interpreted accordingly 8. The following quality control organisms were used: E coli ATCC 25922, Pseudomonas aeruginosa ATCC, Streptcoccus pneumonae ATCC 49619. After agar surface was dry, the following antimicrobial discs were applied: ampicillin 10mg, cotrimoxazole 25mg, clindamycin 2mg, chloramphenicol 30mg, ceftriaxone 30mg, penicillin 2mg, flucloxacillin 5mg, erythromycin 15mg, ciprofloxacin 5mg, Nitrofurantoin 10mg, amoxicillin/clavulinic acid (Augmentin) 20/10mg. The culture plates were incubated both aerobically and anaerobically at 370c for 24 to 48 hours. The results were analysed using statistical package for the social sciences (SPSS) 11.0 software.

Results:

Overall, 18520 isolates were grown on culture from 9 site-specific specimens. In decreasing order of frequency, bacterial isolates were obtained from urine (31.6%), wounds (22.8%), blood (12.4%), genital (7.7%), sputum (6.9%), stool (6.3%), CSF (16.0%), aspirates (3.8%) and ear/throat (2.5%) (Table 2).

Staphylococcus species was the commonest gram positive bacteria isolated from all the specimens (13.6%). Pseudomonas was the most predominant (12.1%) of the gram negative bacteria followed by Escherichia coli (11.2%) (Table 2).

Table 3 shows that only 30% of Staphylococcus aureus was sensitive to penicillin, while 73% and 84% were sensitive to augmentin and ceftriaxone, respectively. Escherichia coli showed 53% and 81% sensitivity to chlorampenicol and augmentin, respectively. But only 58% of them were sensitive to gentamicin.

TABLE 2

Distribution of major groups of bacteria Click here for the Three Day Cleanse & quick fix urine Recipes. isolated from the specimens (n=18,520)

Bacteria Wound Urine Genital Blood Sputum CSF Stool Ear &

Throat

Aspirates Total (%)
Gram positive
Staph. aureus 770 469 353 469 120 60 0 80 190 2511

(13.6)

Strept. Pyogenes 50 0 30 15 130 23 0 50 30 328

(1.8)

Strept. pneumonia 0 0 0 50 380 250 0 80 0 760

(4.1)

Strept. faecalis 18 250 5 0 0 50 50 30 39 442

(2.4)

Strept. viridans 120 20 5 15 150 60 0 30 5 405

(2.2)

Gram

negative

Pseudomonas 1200 600 5 90 40 0 33 20 250 2238

(12.1)

Esch. coli 520 1200 10 90 10 60 50 78 55 2073

(11.2)

Proteus sp. 420 500 30 0 0 0 0 0 0 950

(5.1)

Providencia 250 950 15 0 0 0 0 19 25 1259

(6.8)

Klebsiella 300 1028 23 0 520 0 0 0 0 1871

(10.1)

N. gonorrheae 0 139 950 30 0 0 0 0 0 1119

(6.0)

Salm. typhi 190 390 0 590 10 59 380 53 33 1707

(9.2)

S. paratyphi A 120 180 0 340 0 13 280 13 39 985

(5.3)

S. paratyphi B 90 100 0 280 0 5 190 5 19 689

(3.7)

S. paratyphi C 180 39 0 180 17 8 180 3 28 635

(3.4)

N. meningitides 0 0 0 28 0 520 0 0 0 548

(3.0)

Total (%) 4230

(22.8)

5865

(31.7)

1426

(7.7)

2292

(12.4)

12625

(6.8)

1108

(6.0)

1163

(6.3)

461

(2.5)

713

(3.8)

18520

Table 3: Antibiotic sensitivity pattern of bacteria (Percent).

Bacteria Pen Amp Clox Aug Chl Ery Cot Gen Nit Flu Ceft Clin Cip
Staph. aureus 30 35 60 73 45 56 37 47 - 84 43 56
Strept. pyogenes 84 74 63 94 41 34 46 58 13 43 78 41 73
Strept. pneumon 93 71 63 89 33 37 38 75 28 58 81 40 69
Strept. viridans 58 63 59 81 43 53 38 60 15 45 81 44 70
Esch. coli 0 53 47 81 63 41 54 58 60 63 91 53 75
Proteus 0 53 47 81 63 41 54 58 60 63 91 53 96
Providencia 3 34 41 65 45 3 48 53 50 54 87 51 73
Klebsiella 0 12 17 54 38 12 25 48 17 39 68 48 65
Pseudomonas 0 0 0 20 0 0 0 39 0 5 53 0 58
N. gonorrheae 10 6 3 20 0 0 5 38 0 17 63 58 73
Salm. typhi 0 31 5 48 51 0 28 51 0 18 75 17 81
S. paratyphi: A 0 28 17 53 50 0 41 58 0 15 81 0 83
S. paratyphi: B 0 38 20 61 53 0 50 73 0 28 85 0 90
S. paratyphi: C 0 40 30 71 51 0 48 68 20 31 78 14 81
N. meningitidis 63 58 43 71 53 48 41 63 15 28 74 60 63

pen=penicillin,  amp=ampicillin,  clox=cloxacillin,  aug=augmentin,  chl=chloramphenicol,   ery=erythromycin,  cot=cotrimoxazole,  gen=gentamicin,  nit=nitrofurantoin,  flu=floxacillin,  ceft=ceftriaxone,    cip=ciprofloxacin

Discussion

The majority (76%) of the bacteria isolated from specimens in this study were gram negative. Among these, Pseudomonas and E. coli were the most predominant. This may be due to the fact that E. coli form part of normal gut flora and pseudomonas is abundant on the body surfaces. These bacteria are, therefore expected to be more likely isolated from the urinary tract and wound infections. Some of the infections may also be auto-infections, especially in females. Both organisms showed a lot of resistance to common antibiotic in the community. For example, E. coli showed 47%, 42% and 46% resistance to ampicillin, gentamicin and cotrimoxazole, respectively. This may be as a result of abuse of antibiotics in the area. These drugs are frequently sold by vendors in the community 6,7 .

Pseudomonas species and Staphylococcus aureus were frequently isolated from wound infections. Both organisms are abundant on human surface and natural materials and are more frequently encountered as a cause of wound infection or contamination 5. These were observed to be resistant to most commonly used antibiotics in the hospital i.e. penicillin (70%), ampicillin (65%) and cotrimoxazole (63%).

Neisseria gonorrheae showed resistance rate of 62% to gentamicin. Surprisingly, 47% and 27% resistance was observed with ceftriaxone and ciprofloxacin, respectively.

The resistance rate of Salmonella typhi was 49% with chloramphenicol and gentamicin while 25% and 19% were resistant to ceftriaxone and ciprofloxacin, respectively. It is a dangerous trend as it will soon become difficult to treat typhoid and paratyphoid fevers in the area.

The question is where do we go from here if resistance has now developed to new generation of cephalosporin and ciprofloxacin? If no effort is done to control the use of antibiotic in the community, then we are heading for doom in terms of antibiotic usage. The clinical microbiologist will have an important role in providing his clinical colleagues with the latest studies of prevalence of pathogenic bacteria and their susceptibility patterns 7,9. Such surveillance information can also be used in the formulation policies for the supply and use of antibiotics in the community.

Studies from central Europe show that bacterial resistance to antimicrobial agents has not changed much during the past 10years 9. Also in the US, for the past 12 years, there has been no change in the resistance to antimicrobial agents 10. Geographical variations can affect the antibiotic resistance pattern as was also noticed in the UK; hence there is need for local sentinel surveillance programme 9,10.

In the local environment in Nigeria, the choice of antibiotics is often made and treatment started before laboratory report of susceptibility of the causative organisms is available. So there is need for clinicians to be aware of locally prevalent organisms and their antibiotic susceptibility and resistance patterns. This will guide clinicians for the best choice of antibiotics in our settings.

Earlier studies have shown that education and training programmes for doctors have proved to be very useful in the proper use of antimicrobials 10,11,12. For this success to continue, adequate surveillance of resistance of bacteria to antimicrobial agents must be maintained.

Acknowledgments

Authors wish to record their gratitude to the Department for International Development (DFID) for equipping and upgrading Otukpo General Hospital to a level of research centre. Authors are also grateful to the management of Otukpo General Hospital and the technical staff of laboratories for this study.

References:

1.      Nwadioha S I.  A study of isolates from genital swab specimens in a Nigerian tertiary hospital. Nig  Hosp Pract.  2010; 6(3):65 -68.

2.      Petti CA, Polage CR. Laboratory medicine in Africa: A barrier to effective health care. Clin Infect Dis 2006;42:377-382.

3.      Nwadioha SI, Nwokedi EOP, Ikeh I, Egesie J, Kashibu E. Antibiotic susceptibility pattern of uro-pathogenic bacterial isolates from AIDS patients in a Nigerian tertiary hospital. J Med & Med Sci. December 2010; 1(11):530-534.

4.      Mwansa JC. Mwaba J. Multiply antibiotic resistant Vibrio cholerae 01-biotype  EL-Tor strains emerge during cholera outbreaks in Zambia . Epidemiol Infect 2007; 135:847-853.

5.      Skov R, Jensen ET, Molbak K. MRSA: New guideline and mandatory notification.http//www.ssi.dk/graphics/en/news/epinews/2006/PDF/epinews/44,2006 pdf.

6.      GTA Jombo, S.O Opajobi, DZ Egah, EB Banwat, P. Denen Akaa. Symptomatic vulvovaginal candidiasis and genital colonization by candida species in Nigeria. J Pub Hlth & Epidem. 2010; 2(6):147-151.

7. Betty A, Daniel FS, Alice S (Editors). Bailey & Scotts Hand book of Diagnostic Microbiology. 12th Edition. Mosby Elsevier Publishers 2007. pp 856 -872.

8.      Clinical Laboratory Standard Institute (2006). Performance standard for antimicrobial disk susceptibility tests; Approved standard -9th Ed. Supplement M2 – A9, 26(1).

9.  Nwadioha SI, Nwokedi EOP, Jombo GTA, Alao OO, Kashibu E. Antibiotic susceptibility pattern of uropathogenic bacterial isolates from community – versus- hospital acquired UTI in a Nigerian tertiary hospital. Internet J Infect Dis. 2010;

8(1):10-15. At http://www.ispub.com/journal/ the internet journal of infectious diseases

10.  Stevenson JC, Gay K, Barrett TJ, Angulo FJ. Increase in Nalidixic acid resistance among non-Typhi Salmonella enterica isolates in the USA from 1996 -2003. Antimicrob Agents Chemother 2007; 51: 195-197.

11.  Kay RS, Vandevelde AG. Outbreak of health care associated infection and colonization with multidrug resistant Salmonella enterica serovar senftenberg in Florida. Infect Contrl Hosp Epidemiol 2007;28: 805-901.

12.  Centers for Disease Control and Prevention. National antimicrobial resistance monitoring system for Enterobacteria (NARMS); 2003 human isolates final report. Atlanta, US. Dept of Health and Human Services, 2006.

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