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In-vitro antimicrobial susceptibility pattern of Staphylococcus aureus isolates in Umuahia, Abia state, Nigeria

EO Ekundayo, RN Ndubuisi

 

Abstract

The antimicrobial susceptibility pattern of Staphylococcusaureus in Umuahia was investigated in this study.A total of 113 strains of S. aureusconsisting of 30 isolates from clinical specimens obtained from 10 medical Laboratories and 83 isolates from nasal swabs of University students in Umuahia, were tested against 10 antimicrobial agents using the disc agar diffusion method. Resistance to penicillin, ampicillin, cloxacillin and tetracycline was 100% among strains isolated from clinical specimens. The clinical isolates also exhibited high rates of resistance to chloramphenicol (97%) and erythromycin (97%). Seven (23%) of these isolates were sensitive to Gentamicin and 6 (20%) to Streptomycin. Likewise, all the 83(100%) and 82 (98.8%)were resistant to penicillin and cloxacillin, respectively.Isolates from nasal passages appeared to be less resistant to chloramphenicol (54.2%), gentamicin (43.4), streptomycin (31.3%) and tetracycline (51.8%). Ampicillin did not produce any zone of inhibition against 29 (96.7%) isolates from clinical specimens and only slightly inhibited one with zone of inhibition of 8mm. Nineteen of the isolates manifested low to high level of resistance to chloramphenicol with mean zone of inhibition ranging from 15. 8± 0.7 mm to 9.8± 2.0 mm. All the isolates were completely resistant to penicillin and cloxacillin with no zone of inhibition at all. In the case of gentamicin, 5 (16.7%) had intermediate susceptibility (mean zone of inhibition 14±0 mm), 12(40%) had mean inhibition zone of 9.6±2.9 mm and 6(20%) were not inhibited. This study shows that S. aureus strains isolated from clinical specimens and healthy students in Umuahia are highly resistant to common antibiotics. This may not be unconnected with indiscriminate use of antibiotics and calls for more control and rational use of antibiotics to minimize the rate of development of resistance to other antibiotics.

Key words: Staphylococcus aureus, antimicrobial resistance, disc agar diffusion, antibiotic susceptibility

French Abstract

Le profil de sensibilité antimicrobienne de Staphylococcus aureus à Umuahia a été recherché dans cette étude. Au total, 113 souches de S. aureus composé de 30 souches provenant d’échantillons cliniques obtenus à partir de 10 laboratoires médicaux et 83 souches d’écouvillons nasaux des étudiants universitaires à Umuahia, ont été testées contre 10 agents antimicrobiens par la méthode de diffusion disque sur gélose. La résistance à la pénicilline, l’ampicilline, la cloxacilline et la tétracycline a été de 100% chez les souches isolées d’échantillons cliniques. Les souches cliniques ont également présenté des taux élevés de résistance au chloramphénicol (97%) et à l’érythromycine (97%). Sept (23%) de ces souches étaient sensibles à la gentamicine et 6 (20%) à la streptomycine. De même, tous les 83 (100%) et 82 (98,8%) étaient résistants respectivement à la pénicilline et à la cloxacilline. Les souches de voies nasales semblaient être moins résistantes au chloramphénicol (54,2%), à la gentamicine (43,4), à la streptomycine (31,3%) et à la tétracycline (51,8%). L’ampicilline n’a produit aucune zone d’inhibition contre 29 (96,7%) souches provenant d’échantillons cliniques et seulement légèrement inhibées avec une zone d’inhibition de 8mm. Dix-neuf souches ont manifesté un faible niveau élevé de résistance au chloramphénicol avec une zone d’inhibition moyenne allant de 15. 8 ± 0,7 mm à 9.8± 2,0mm. Toutes les souches étaient complètement résistantes à la pénicilline et à la cloxacilline sans zone d’inhibition. Dans le cas de la gentamicine, 5 (16,7%) souches avaient une sensibilité intermédiaire (zone d’inhibition moyenne de 14 ± 0 mm), 12 (40%) souches ont eu une zone d’inhibition moyenne de 9,6 ± 2,9 mm et 6 (20%) souches ne ont pas été inhibées. Cette étude montre que les souches de S. aureus isolées  à partir d’échantillons cliniques et des étudiants en bonne santé à Umuahia sont très résistantes aux antibiotiques courants. Cela peut ne pas être en rapport avec l’utilisation sans discernement des antibiotiques et des appels pour plus de contrôle et d’utilisation rationnelle des antibiotiques afin de minimiser le taux de développement d’une résistance à d’autres antibiotiques.

Mots clés: Staphylococcus aureus, résistance aux antimicrobiens, disque de diffusion sur gélose, sensibilité aux

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In-vitro antimicrobial susceptibility pattern of Staphylococcus aureus isolates in Umuahia, Abia state, Nigeria

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In vitro and in vivo antimicrobial activity of partially purified enterocin produced by Enterococcus faecalis and its application in wound healing

O.M. David, M.O. Alese, D.M. Komolafe, I.J. Adejare, O.O. Alese, A.E. Omonisi

 

Abstract

Background: The recent global upsurge in antibiotic resistance among bacteria associated with wounds has contributed to high treatment failures in wound management. Enterocin are produced by enterococci and has been reported to inhibit the growth of many bacteria including those associated with wound infections.

Objectives: In this study, antibacterial and physico-chemical properties of partially purified enterocin (PPE) from Enterococcus faecalis was determined. Also, the possible application of the enterocin in wound management was evaluated.

Materials and Methods: Eight different enterocin were tested and that with highest antibacterial (E3) was partially purified using standard methods. The molecular weight of the PPE was determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis after which the in vitro anti-Staphylococcus aureus potential of the PPE was determined.

Results: Enterocin (E3) was effective against Staphylococcus aureus, Klebsiella pneumoniae, Enterobacter cloaca, Listeria monocytogenes and Proteus vulgaris. The activity of the E3 was very prominent at pH of 4 and 8. The molecular size of the isolated enterocin was 5.5 KDa. The photomicrograph of the skin tissue of the skin treated with partially purified enterocin for day 7showed epidermis covered by atrophic stratified squamous epithelium. A synergistic interaction was noticed when Eusol was used with the enterocin.

Conclusions: From this study, enterocin from E. faecalis has a low molecular weight and inhibited bacteria isolates from wound and also aids physiological healing of wound.The antibacterial potency of this bacteriocin indicates that it is an alternative therapeutic agent that can be employed in wound care and management.

Keywords: Enterocin, Enterococcus faecalis, wounds, bacteriocin, Staphylococcus aureus, skin

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In vitro and in vivo antimicrobial activity of partially purified enterocin produced by Enterococcus faecalis and its application in wound healing

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Incidence and Distribution of Multi-Drug Resistant Pathogens from Clinical Samples in a Tertiary Hospital in South-South Nigeria

O Iyoha, MY Tula

 

Abstract

Background
Antibiotics have proven to be a dynamic category of drugs in the fight against infectious bacteria. However, antibiotic
resistance is one of the greatest current challenges to the effective treatment of infections and there is every indication that
antibiotic resistance will become an even greater challenge in the future.
Methodology
Ten clinical samples with varying frequencies were analyzed for bacterial growth, antibiotic susceptibility testing and
multiple antibiotic resistances. The clinical samples includes; urine (42%), wound swab (21.33%), blood (10%), ear swab
(9.33%), catheter tip (5.33%), endocervical swab (4.67%), high vaginal swab (HVS) (2.67%), urethral swab (2.67%), pus
(1.33%) and antral aspirate (0.67%).
Results
A total of 150 bacterial isolates distributed among these ten (10) clinical samples were identified, of which Staphylococcus
aureus (30%) was the most predominant, while Klebsiella oxytoca, Citrobacter spp. and Streptococcus spp. were the least
(0.67%). These were tested for sensitivity against 9 antibiotics. The resistance rate observed was as follows; cefuroxime
(93%), ceftazidime (87%), gentamycin (79%), augmentin (70%), cloxacillin (67%), ofloxacin (54%), ciprofloxacin (51%),
ceftriaxone (38%) and ocefix (34%). One hundred and forty-three (95.3%) of the isolates showed multiple resistance against
3 – 8 antibiotics. None was resistant to as few as 1 – 2 antibiotics.
Conclusion
The high susceptibility to some antibiotics such as ceftriaxone and ocefix could be a welcoming relief, since they can be
used to address the problem of resistance in this area. There is need for nationwide surveillance programme to monitor
microbial trends and antimicrobial resistance patterns in Nigeria.

Key words: multi-drug resistant, clinical samples, Staphylococcus aureus, ocefix.

 

Contexte
Les antibiotiques se sont démontrés être une catégorie dynamique des médicaments pour lutter contre les infections
bactériennes. Cependant, la résistance aux antibiotiques est l’un des grands défis actuels pour le traitement efficace des
infections et tout porte à croire que la résistance aux antibiotiques devient un défi encore plus grand à l’avenir.
Méthodologie
Dix échantillons cliniques avec leurs grandes fréquences ont été analysés par la culture bactériennes, le teste de sensibilité
aux antibiotiques et le teste de la multirésistance aux antibiotiques. Les échantillons cliniques sont constitués de l’urine
(42%), de pus de la plaie (21,33%), de sang (10%), de prélèvement d’oreille (9,33%), d’extrémité du cathéter (5,33%), de
prélèvement d’endocervical (4,67%), de prélèvement vaginal (2,67%), de prélèvement urétral (2,67%), de pus (1,33%), de
ponctionantrale(0,67%).
Résultats
Au total, 150 souches bactériennes réparties parmi les dix (10) échantillons cliniques ont été identifiées, parmi lesquelles
Staphylococcus aureus (30%) était le plus prédominant, alors que Klebsiellaoxytoca,Citrobacter spp et Streptococcus spp
étaient les moindres (0,67%). Ils ont été testés pour la sensibilité de 9 antibiotiques. Le taux de résistance observé était le suivant: céfuroxime (93%), ceftazidime (87%), gentamicine (79%), augmentin (70%), cloxacilline (67%), ofloxacine (54%),
ciprofloxacine (51%), ceftriaxone (38%) etocefix (34%). Cent-quarante-trois (95,3%) d’isolats ont montré la multi-résistance
contre 3 à 8 antibiotiques. Aucune souche n’a été résistante à moins de 1 à 2 antibiotiques.
Conclusion
La forte sensibilité de certains antibiotiques tels que la ceftriaxone et l’ocefix pourraient être un ouf de soulagement, car ils
peuvent être utilisés pour résoudre le problème de la résistance dans cette région. Il est nécessaire pour le programme
national de surveillance pour suivre les tendances microbiennes et les situations de résistance aux antimicrobiens au
Nigeria.

Mots clés: multi-résistance aux antibiotiques, échantillons cliniques, Staphylococcus aureus, ocefix.

Article in English.

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Incidence and Distribution of Multi-Drug Resistant Pathogens from Clinical Samples in a Tertiary Hospital in South-South Nigeria.

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Antibacterial properties of Mangifera indica on Staphylococcus aureus

J Mushore, M Matuvhunye

 

Abstract

Antibacterial activity of Mangifera indica stem bark extracts was determined using disk diffusion, agar and broth dilution methods. In disk diffusion method, inhibition zone sizes were used to determine the susceptibility of S. aureus to the extracts. The results showed that the stem-bark extracts of M. indica have antimicrobial activity against S. aureus. Methanol extracts showed the highest inhibition zone diameter of 25 mm, followed by ethyl acetate, water and hexane extracts with inhibition zone diameter of 22 mm, 14 mm and 10 mm, respectively. The antibacterial activities of different extracts were found to be concentration dependent, in agar and broth dilution methods. The plant extracts were shown to have a MIC range of 0.62 mg/ml to 4.17 mg/ml, in agar dilution method. Results from the broth dilution method had a MIC range of 0.16 mg/ml to 1.25 mg/ml. The control (ampicillin) was however, more effective than plant extracts since only a concentration of 0.03 mg/ml in agar dilution and 0.001 mg/ml in broth dilution method were effective to inhibit the growth of S. aureus. The extracts were shown to be bacteriostatic at low concentrations. Phytochemical screening of the extracts revealed the presence of phyto-compounds such as alkaloids and tannins which are known to inhibit bacterial growth by different mechanisms from those of synthetic drugs. These phyto-constituents may be responsible for the M. indica antibacterial
activity.

Keywords: Staphylococcus aureus, antimicrobial activity, MIC, Phytochemical screening, MBC.

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Antibacterial properties of Mangifera indica on Staphylococcus aureus

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In vitro effect of some quinolone antibiotics on strains of Staphylococcus aureus isolated from a hospital environment

RK Obi, FC Nwanebu

 

Abstract

A total of 30 different strains of Staphylococcus aureus were isolated from some selected wards of Madonna University Teaching Hospital (MUTH), Elele, Nigeria, using blood agar and nutrient agar. All the isolates were subjected to some selected quinolones (ciprofloxacin, pefloxacin, ofloxacin, norfloxcin and sparfloxacin) to determine their antibiotic susceptibility pattern using the disk diffusion method. Ofloxacin had the highest percentage
susceptibility of 93.3%, followed by ciprofloxacin with 73.3%; pefloxacin was next with 70%, sparfloxacin 63.3%, while norfloxacin recorded the lowest percentage of 50%. The minimum inhibitory concentration (MIC) of the quinolones to the isolates was also determined. The results show that all the tested quinolones had an MIC ranging from 2.5-10mg/ml.

Keywords: Staphylococcus aureus, quinolones, hospital environment

African Journal of Clinical and Experimental Microbiology Vol. 9 (3) 2008: pp. 142-146

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Pattern of resistance to vancomycin and other antimicrobial agents in staphylococcal isolates in a university teaching hospital

BO Olayinka, AT Olayinka, JA Onaolapo, PF Olurinola

 

Abstract

Multidrug resistance has been reported in clinical isolates of both coagulase-negative staphylococci (CoNS) and Staphylococcus aureus that are most often resistant to oxacillin/methicillin. Vancomycin, a glycopeptide is the drug of choice for infections caused by such multidrug resistant strains. This study determined the pattern of resistance to vancomycin and other antimicrobial agents in staphylococcal isolates from a University Teaching Hospital. Staphylococcal isolates from clinical specimens submitted to the diagnostic medical microbiology laboratory of the Ahmadu Bello University Teaching Hospital, Zaria (over a three-month period) were characterized using standard microbiological procedures and their susceptibility to vancomycin and other commonly used antimicrobial agents determined by Kirby-Bauer-NCCLS modified disc diffusion technique. A total of 56 of the 97 (57.7%) staphylococcal isolates characterized were resistant to vancomycin 30μg, showing a zone of inhibition less than 15mm. Most of these isolates were from urine (27.3%), wound (21.8%) and pleural aspirate (12.8%). The 56 staphylococcal isolates were made up of 75% (41/56) Staphylococcus aureus and 25% (14/56) coagulase-negative staphylococci. Majority of the isolates, 60.7% (34/56) produced β-lactamase enzyme. Resistance pattern to other antimicrobial agents was benzyl penicillin G (92.9%); tetracycline (69.6%); cefuroxime (60%); chloramphenicol (54.5%); oxacillin (49.1%); erythromycin (35.7%); gentamicin (25%) and ciprofloxacin (16.1%). Analysis of the multiple antibiotic resistance index (MARI) showed that majority (91.1%) were resistant to 3 to 7 of the other antimicrobial agents tested. No isolate was resistant to all the tested antimicrobial agents. A very high proportion of the staphylococcal isolates were resistant to vancomycin, a glycopeptide that is not commonly used in this environment. Ciprofloxacin and gentamicin appear to be the only agents that will be effective in treating infections by these isolates. The high proportion of isolates with MARI of 0.3 and above, suggest that the isolates originated from an environment where antibiotics are often used. There is need for constant, on-going antimicrobial resistance surveillance in important and commonly isolated clinically significant pathogens to form the basis for developing and implementing measures that will reduce the burden of antimicrobial resistance.

Key Words: vancomycin, methicillin resistance, Staphylococcus aureus, coagulase-negative staphylococci, antimicrobial agents

Afr. J. Clin. Exper. Microbiol. Vol.6(1) 2005: 21-27

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METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS (MRSA) ISOLATES IN ILORIN, NIGERIA

SS Taiwo, BA Onile, AA Akanbi II

 

Abstract

Nosocomial infections caused by methicillin-resistant strains of Staphylococcus aureus often pose therapeutic dilemma to the clinicians because of the multi resistant nature of these strains of Staphylococcus aureus. Outbreaks of both nosocomial and community acquired infections are also frequent and difficult to control. This study determined the prevalence and antimicrobial susceptibility pattern of methicillin-resistant Staphylococcus aureus (MRSA) at the University of Ilorin Teaching Hospital, between January and December 2001. The methicillin disc diffusion method for the detection of methicillin resistance and the Kirby-Bauer disc diffusion for antibiotic susceptibility tests, were used. The MRSA prevalence rate was 34.7% (51/147) of all Staphylococcus aureus isolates. Forty-five isolates were associated with infections and 6 were colonizing strains. Thirty-six (70.6%) were hospital (nosocomial) acquired while 15 (29.4%) were community-acquired. Forty-eight patients have received antibiotics previously including 30 who had received multiple antibiotics. Skin and soft tissues were sites of infections in 36 cases and surgical, emergency and intensive care units accounted for 31 isolates. All MRSA isolates were resistant to more than two antibiotics but remained largely susceptible to third generation cephalosporins, macrolides and quinolones and all were sensitive to vancomycin. We recommend the use of third generation cephalosporins and quinolones where indicated, in the treatment of serious MRSA infections in this environment. Control of the spread of MRSA in this hospital must include reinforcement of appropriate use of antibiotics, hand washing and laboratory surveillance for MRSA, particularly in the surgical wards and intensive care units, in order to identify sources of outbreaks.

Key Words: Methicillin-resistant, Staphylococcus aureus, Ilorin.

Afr. J. Clin. Exper. Microbiol. 2004; 5(2): 189 – 197.

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METHICILLIN RESISTANCE IN STAPHYLOCOCCAL ISOLATES FROM CLINICAL AND ASYMPTOMATIC BACTERIURIA SPECIMENS: IMPLICATIONS FOR INFECTION CONTROL

B.O. Olayinka, A.T. Olayinka

 

Abstract

The study assessed the importance of Staphylococcus aureus as a urinary pathogen and the incidence of multidrug resistant (MDR), methicillin-resistant Staphylococcus aureus (MRSA). A total of 86 staphylococcal isolates made up of 50 clinical isolates from urine samples submitted to the Medical Microbiology Laboratory of Ahmadu Bello University Teaching Hospital and 36 asymptomatic bacteriuria isolates from urine samples of ‘healthy’ volunteers within the university community were tested for their susceptibility to various antibiotics and production of b-lactamase enzyme. A total of 27 isolates (31.4%) were methicillin resistant, with 12(44.4%) being methicillin resistant coagulase-negative staphylococci (MRCNS). Majority of the isolates tested were resistant to the cheap, readily available broad-spectrum antibiotics; ampicillin, amoxicillin, chloramphenicol, tetracycline and penicillin G. All the isolates were resistant to three or more of the antimicrobial agents tested. A total of 14/50 (28%) of the clinical isolates and 17/36 (47.2%) of the ‘community’ isolates from healthy volunteers were resistant to 7 or more of the antimicrobial agents tested. Analysis of the multiple antibiotic resistance (MAR) index of isolates and the production of b-lactamase enzyme showed that 56 isolates representing 65.1% of the total number tested had an MAR index of 0.5 and above indicating that they probably originated from an environment where antibiotics are frequently used. The implication of these findings for instituting effective control measures aimed at reducing the pool of antibiotic-resistant organisms is discussed.

Key words: Methicillin-resistant, staphylococcus aureus, asymptomatic bacteriuria, infection control
(Af J Clinical & Exp Microbiology: 2003 4(2): 79-90)