High levels of multidrug resistance in clinical isolates of Gram-negative pathogens from Nigeria.

In Nigeria, quinolones and ß-lactam antibiotics are widely used to treat bacterial infections. This study aimed to identify the prevalence of resistance to these drugs and to determine the mechanisms of resistance to these agents. In total, 134 non-duplicate, Gram-negative enteric isolates of 13 species from different hospitals were investigated for susceptibility to a panel of antibiotics, carriage of plasmid-mediated quinolone and ß-lactam resistance genes, production of extended-spectrum ß-lactamases (ESBLs), and mutations within topoisomerase genes. The level of resistance to all antibiotics tested was extremely high, with minimum inhibitory concentrations for 90% of the organisms (MIC(90) values) of ≥ 256 µg/mL for all drugs. Of the 134 isolates, 92 had mutations within the quinolone resistance-determining region (QRDR) of gyrA or within gyrA and parC. In addition, the plasmid-mediated quinolone resistance genes qnrA, qnrB, aac(6')-Ib-cr and qepA were identified. The qnrD allele, which has previously only been found in Salmonella isolates from China, was identified in two Proteus isolates and one Pseudomonas isolate. Of the 134 isolates, 23 (17.2%) carried aac(6')-Ib-cr, 11 (8.2%) carried a qnr variant and 5 (3.7%) were positive for qepA. Twenty-eight isolates (20.9%) produced ESBL variants, with a CTX-M variant being carried by 25 isolates (18.7%). In addition, six isolates (4.5%) carried ampC variants [ACT-1 (1 isolate), DHA-1 (4 isolates) and CMY-2 (1 isolate)]. This study demonstrates a very high level of multidrug resistance amongst Gram-negative enteric bacilli isolated from different sites from patients in Nigerian hospitals as well as the presence of a variety of plasmid-associated resistance genes, including some identified from Africa for the first time.

Antibiotic susceptibility patterns of Pseudomonas aeruginosa to available antipseudomonal drugs in Ibadan, Nigeria.

Pseudomonas aeruginosa has been reported to be a leading cause ofnosocomial infections. Resistance of this notorious bacterium to commonly used antimicrobial agents is becoming an increasing clinical problem and a recognized public health threat because there are limited number of antimicrobial agents including the antipseudomonal penicillins, cephalosporins, carbapenems, aminoglycosides and fluoroquinolones with reliable activity against it. This study was therefore carried out, using Bauer-Kirby method, to determine the antibiotic susceptibility patterns of Pseudomonas aeruginosa isolates from in-patients and out-patients attending the University College Hospital, Ibadan in Nigeria between June 2004 and May 2006. The isolation rate of Pseudomonas aeruginosa in clinical specimens was found to be 16.8% with the highest occurrence of 41.9% in ear swab followed by 39.3% occurrence in wound swab. The susceptibility pattern showed that 78.3% were sensitive to amikacin and 72.0% to ciprofloxacin. The isolates from the in-patients showed higher resistance to all the antibiotics tested than the isolates from the out-patients, most especially amikacin and ciprofloxacin. However, no consistent antibiotic susceptibility pattern could be established for this pathogenic bacterium based on sources. In conclusion, the Pseudomonas aeruginosa species harboured by in-patients showed higher rates of antibiotic resistance than those of the out-patients. Also amikacin and ciprofloxacin were the two antibiotics found to be most potent against this pathogen.

Fluconazole resistant opportunistic oro-pharyngeal Candida and non-Candida yeast-like isolates from HIV infected patients attending ARV clinics in Lagos, Nigeria.

BACKGROUND: Oro-Pharyngeal Candidiasis (OPC) continues to be considered the most common opportunistic fungal disease in HIV/AIDS patients globally. Azole antifungal agent has become important in the treatment of mucosal candidiasis in HIV patients. Presently, antifungal drug resistance is fast becoming a major problem particularly with the immune depleted population. OBJECTIVES: This study was designed to investigate the: existence of OPC, species distribution fluconazole susceptibility profile of yeast cells isolated from oral specimens of HIV/AIDS patients from Lagos Nigeria, between Oct. 2004 and June, 2005. METHODOLOGY: The venous blood samples were screened for HIV antibodies using the Cappillus HIV I and II test kit (Trinity Biotech Plc UK), and Genie II HIV I and II EIA kit (Bio-Rad France). The positive results were subsequently confirmed at the laboratory attached to each of the clinics, using the Nigerian Federal Ministry of Health approved algorithm. The samples from 213 (108 females and 105 males) HIV positive patients were plated onto SD agar. The isolates were identified by morphotyping, microscopy and speciated using germ tube test and battery of biochemical sugar fermentation and assimilation tests. Fluconazole agar diffusion susceptibility testing was carried out on each isolates. RESULTS: Seventy-four (34.7%) isolates were recovered including one person with double isolates. Only 70 (94.6%) of the isolates could be adequately speciated. Candida albicans 30 (40.5%) was the most frequently isolated species, the rest were non-albicans species, with the frequency of C. tropicalis > C. Krusei > C. glabrata and C. neoformans for species for species having up to 4 isolates. Four (30.8%) out of 13 isolates of C. tropicalis showed germ tube formation. While one C. albicans was germ-tube negative. Out of the 74 isolates tested for fluconazole sensitivity, 58 (78.4%) were sensitive, MIC d'' 8 microg/ml, 9 (12.1%) were susceptible Dose Dependent (SDD), MIC 16-32 microg/ml and 7 (9.5%) were resistant, MICs e'' 64 microg/ml. Among the C. albicans isolates, 26 (86.7%) were sensitive to fluconazole. The rank of susceptibility was C. albicans > C. tropicalis > C. Krusei for the most prevalent species. CONCLUSION: We conclude that fluconazole resistant strains of oro-pharyngeal yeast-like cells exist in about 9.5% of HIV/AIDS patients with the above stated species distribution. We therefore, highlight the need for routine antifungal susceptibility testing on HIV patients with cases of initial or repeat episodes of OPC.

Plasmid determined resistance to quinolones in clinical isolates of Gram-negative bacilli.

A total of 166 strains of Gram-negative bacilli comprising 65 Klebsiella species, 22 Escherichia coli, 39 Pseudomonas aeruginosa, 20 Proteus species, 18 other Pseudomonas species and 2 Salmonella typhi, were isolated from clinical specimens in the University College Hospital, Ibadan. Antimicrobial susceptibility testing and plasmid profiling of the strains were done. Ceftazidine had the highest antibacterial activity of 83.1% compared to the fluoroquinolones followed by ciprofloxacin (78.3%), pefloxacin (69.9%) and ofloxacin (56%) respectively. Of the 166 strains, 44 were found to be resistant to most of the antimicrobial agents tested. Resistance to ofloxacin was common among the resistant strains. The resistant strains harboured plasmids with molecular sizes ranging from 6.6kb to 17.4kb and were grouped into five plasmid profile groups. Transformation experiment showed that 59.2% of the resistant strains carried a common R-plasmid of size 10.7kb. Resistance to ciprofloxacin and pefloxacin were found to be plasmid borne.

Levels and interactions of plasma xanthine oxidase, catalase and liver function parameters in Nigerian children with Plasmodium falciparum infection.

Elevated plasma levels of xanthine oxidase and liver function parameters have been associated with inflammatory events in several human diseases. While xanthine oxidase provides in vitro protection against malaria, its pathophysiological functions in vivo and interactions with liver function parameters remain unclear. This study examined the interactions and plasma levels of xanthine oxidase (XO) and uric acid (UA), catalase (CAT) and liver function parameters GOT, GPT and bilirubin in asymptomatic (n=20), uncomplicated (n=32), and severe (n=18) falciparum malaria children aged 3-13 years. Compared to age-matched control (n=16), significant (p<0.05) elevation in xanthine oxidase by 100-550%, uric acid by 15.4-153.8%, GOT and GPT by 22.1-102.2%, and total bilirubin by 2.3-86% according to parasitaemia (geometric mean parasite density (GMPD)=850-87100 parasites/microL) was observed in the malarial children. Further comparison with control revealed higher CAT level (16.2+/-0.5 vs 14.6+/-0.4 U/L; p<0.05) lacking significant (p>0.05) correlation with XO, but lower CAT level (13.4-5.4 U/L) with improved correlations (r=-0.53 to -0.91; p<0.05) with XO among the asymptomatic and symptomatic malaria children studied. 75% of control, 45% of asymptomatic, 21.9% of uncomplicated, and none of severe malaria children had Hb level>11.0 g/dL. Multivariate analyses further revealed significant (p<0.05) correlations between liver function parameters and xanthine oxidase (r=0.57-0.64) only in the severe malaria group. We conclude that elevated levels of XO and liver enzymes are biochemical features of Plasmodium falciparum parasitaemia in Nigerian children, with both parameters interacting differently to modulate the catalase response in asymptomatic and symptomatic falciparum malaria.

Substrate profile variation and drug resistance patterns of â - lactamase producing Shigella species isolated from diarrhoeal patients in Lagos, Nigeria.

The number and trend of antibiotic resistance by Shigella species recovered from food and diarrhoeal stools are on the increase in Nigeria and has resulted in a high frequency of hospitalisation. Increased cost of disease management, and higher mortality in children. This study exposes 51 â-lactamase producing Shigella isolates from Lagos to some newly introduced drugs in the country. The drugs include â-lactam - â-actamase inhibitor antibiotics. â-lctam substrate hydrolysis and inhibitory effects of clavulanate were also investigated in-vitro. Results obtained revealed that all the isolates showed high level resistance to tetracycline, ampicillin, streptomycin, co-trimoxazole and amoxicillin with an MIC range of 128 - 1024 microg/ml. The isolates were susceptible to piperacillin, tobramycin, aztreonam and ofloxacin (0.03 - 8 microg/ ml). 18.2 - 40.9% of S. flexneri and S. dysenteriae showed low level resistance to cefuroxime and cefotaxime (MIC = 4 - 16 microg/ ml). Among the â-lactam - â- lctamase inhibitors tested, only piperacillin-tazobactam showed 100% resistance. Hydrolysis of â -lctam substrate was found to be species dependent in decreasing order of S. flexneri, S. dysenteriae, S. sonnei and S.boydii. An IC50 range of 0.8-2.4 mM was also observed in these isolates. Our data indicate that the incidence of multidrug resistance is high among â-lactamase producing Shigella isolates in Lagos, Nigeria. While the third generation cephalosporins should be used with cautions, some of the newly introduced drugs have the prospects of being used in the future control and management of shigellosis in the country.

In vitro antimicrobial properties of aqueous garlic extract against multidrug-resistant bacteria and Candida species from Nigeria.

The antimicrobial effects of aqueous garlic extract (AGE) against 133 multidrug-resistant gram-positive and gram-negative bacterial isolates, including Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, Streptococcus pyogenes, Haemophilus influenzae, Salmonella typhi, Pseudomonas aeruginosa, Escherichia coli, Shigella spp., and Proteus spp., and against 10 Candida spp. were studied. Antibacterial activity of AGE by well-diffusion and macrobroth dilution method was characterized by inhibition zones of 20.2-22.7 mm for gram-positives and 19.8-24.5 mm for gram-negatives and minimum inhibitory concentration (MIC) ranges of 15.6-48.3 mg/mL and 22.9-37.2 mg/mL, respectively. With the exception of P. aeruginosa, the observed disparity in MIC values at 24 and 48 hours was not significant (P >.05) in these isolates. The anticandidal effect of AGE resulted in a growth inhibition zone of 27.4 +/- 3.7 mm with no significant difference (P >.05) in MIC values at 24 and 48 hours, respectively. Minimum fungicidal concentrations were found to be 14.9 and 15.5 mg/mL, respectively, at these incubation periods. Further analysis revealed the antimicrobial efficacy of AGE to be dose and time dependent, producing five distinct time-kill profiles among the isolates tested. The results of this study support the use of garlic in health products and herbal remedies in Nigeria.

Patterns and properties of haemagglutinins expressed by Shigella serogroups in Lagos, Nigeria.

Forty-five strains of Shigella were screened for haemagglutinin production and broad-spectrum haemagglutination reaction. Mannose-sensitive haemagglutinin (MSHA) was found in 22 strains [Shigella flexneri (7), S. dysenteriae (7), S. sonnei (3), and S. boydii (5)]. Eighteen strains harboured mannose-resistant haemagglutinin (MRHA), and 8 strains were observed to be non-haemagglutinating to guinea pig erythrocyte. With the exception of human erythrocytes (O, A, B, and AB), the observed MSHA and MRHA also agglutinated the erythrocytes of rabbit, sheep, rat, chicken, and horse, suggesting a broad-spectrum haemagglutinating property. Haemagglutinins of S. flexneri and S. dysenteriae elicited a relatively stronger haemagglutinating activity with agglutinability to chicken and rabbit erythrocytes enhanced by trypsinization. Haemagglutination reaction with guinea pig erythrocyte was generally inhibited by sialic acid, while simple sugars, such as D-glucose, D-galactose, N-acetylgalactosamine, N-acetylglucosamine, and D-rhamnose, elicited no inhibitory effect. The results of the study revealed broad-spectrum haemagglutinin expression by circulating Shigella strains in Nigeria.

A report of clinical trial conducted on Toto ointment and soap products.

OBJECTIVE: The efficacy of Toto ointment and soap on common skin disorders was tested. METHODOLOGY: A cohort of Nigerians with common skin conditions such as fungal and bacterial skin infections, scabies, acne vulgaris, and dandruff were selected and followed for a period of 12 weeks. The study is a randomized, comparative, prospective, blinded observational study. Following a placebo run in/wash out period, patients were given either a Toto ointment or soap, or a combination of these, or sulfur ointment alone. Soap use was preferred in patients with Tinea capitis more than patients with any other superficial skin condition for technical reasons--such as ease of application of the soap lather. Expressed preference for either the soap or the cream was at times taken into consideration. Cure rate, adverse drug effects and acceptability of the products were assessed. RESULTS: Out of the 595 patients with common skin diseases selected for the study, 446 (74.9%) had fungal infections, while 64 (10.8%) had scabies infestation. A total of 47 (7.9%) patients had bacterial skin infections, 36 (6.1%) had acne vulgaris, and two (0.3%) had dandruff. At the end of the treatment period, out of the 129 patients with fungal infections treated with Toto ointment alone, 92 (71.3)% were successfully treated; while 41 (87.2%) out of the 47 patients with scabies were successfully treated with Toto ointment alone. Although few patients were seen with bacterial skin infections during the study period, these patients responded well to the ointment, the soap or a combination of the two. Overall, the combination of Toto ointment and soap had a better clinical success rate on all diseases when compared to sulfur ointment alone. The study has shown the efficacy and tolerability of Toto products (skin ointment and soap) in the management of common skin disorders. CONCLUSION: Toto ointment and soap are particularly efficacious in the management of common skin conditions such as fungal and bacterial skin infections, scabies, acne vulgaris and dandruff.

Impact of asymptomatic maternal malaria parasitaemia at parturition on perinatal outcome.

A cross-sectional study involving 564 parturients who delivered singleton babies and 214 matched non-pregnant controls was carried out to determine the prevalence and impact of asymptomatic maternal malaria parasitaemia at parturition on the perinatal outcome. One hundred and forty (24.8%) parturients and 50 (23.4%) non-pregnant women were found to have asymptomatic malaria parasitaemia, respectively, while the congenital malaria rate in the neonates of the parasitaemic parturients was 0.7%. The incidence of malaria parasitaemia was higher in the para 2 and over (29.33%) as compare to the para 1 (21.43%) and primigravid (18.42%). There was no significant difference between the mean birth weight of infants delivered by parasitaemic parturients (2.93+/-0.61 kg) and aparasitaemic parturients (3.07+/-0.32 kg) (P=0.501). There was also no significant difference when comparing the mean placental weight of the parasitaemic mothers (0.60+/-0.15 kg) with that of the aparasitaemic mothers (0.62+/-0.20 kg) (P=0.329). Only in the para 2 and over was the mean placental weight of the parasitaemic mothers significantly lower than that of the aparasitaemia mothers (0.46+/-0.16 kg; 0.66+/-0.23 kg P=0.035). The mean packed cell volume of the parasitaemics parturients (30.89+/-1.87) was significantly lower than the aparasitaemic parturients (31.98+/-2.25) (P<0.001). Significant difference was not achieved between the parasitaemics and aparasitaemics inrespect of apgar score at 1 minute, or at 5 minutes, premature births (16.43%; 15.33%; P>0.05), stillbirth rate (3.57%; 2.59, P>0.05), mean placental index (0.204, 0.202, P>0.50) and mode of delivery. The findings in this study show that even though malaria parasitaemia is prevalent in our locality, the effects on maternal and fetal wellbeing are comparable with the aparasitaemics.

Epidemiology of shigellosis in Lagos, Nigeria: trends in antimicrobial resistance.

Antimicrobial susceptibility of Shigella spp. and Escherichia coli, isolated from diarrhoeal patients in Lagos, was studied from March 1999 to February 2000. Four hundred fifty-nine isolates were identified as shigellae (62) and E. coli (397). Shigella flexneri, S. dysenteriae, S. boydii, and S. sonnei accounted, respectively, for 51.6%, 17.7%, 17.7%, and 13% of the total number of shigellae isolated. Eleven cases of shigellosis occurred in the age group of 0-9 years, 22 cases in the age group of 10-19 years, and 29 cases in the age group of > or = 20 years. Of the 397 E. coli isolates, 11 were enteropathogenic E. coli (EPEC), and 7 of these strains were isolated with shigellae from stools of patients aged 0-9 year(s) (71.4%) and 10-19 years (28.6%). Over 70% of the Shigella isolates were resistant to two or more drugs, including ampicillin and tetracycline. Twenty-one distinct multidrug resistance patterns were observed in these isolates. During 1990-2000, resistance to ampicillin increased from 70% to 90%, co-trimoxazole from 77% to 85%, chloramphenicol from 71% to 77%, streptomycin from 71% to 79%, and nalidixic acid from 0% to 11.3%. Resistance to tetracycline decreased from 89% to 79% but with MIC50 and MIC90 values outside the susceptible range. While resistance to ciprofloxacin and ofloxacin remained nil with MIC50 and MIC90 values of 0.008 and 0.0016 microgram/mL respectively. The results of this study revealed the endemicity of shigellosis with S. flexneri as the predominant serogroup in Lagos. Children and young adults were at a higher risk of severe shigellosis. The results also suggest that ampicillin, tetracycline, co-trimoxazole, and streptomycin should not be used as the first-line drugs in the treatment of shigellosis. Nalidixic acid should still be selectively used for treatment, while ciprofloxacin and ofloxacin can be ideal alternatives.

Asymptomatic significant bacteriuria among pregnant and non-pregnant women in Sagamu, Nigeria.

In a study carried out among 510 pregnant and 304 non-pregnant women at Ogun State University Teaching Hospital, Sagamu, 122 (23.9%) of the pregnant women and 37 (12.2%) of the non-pregnant women had significant bacteriuria. The rate amongst the pregnant women was significantly higher than in non-pregnant women (P < 0.001). There was a correlation between pyuria and significant bacteriuria in 45 (8.8%) of the pregnant women and in 11 (3.6%) of the non-pregnant women. Significant bacteriuria was closely associated with nulliparae. Most of the pregnant women with significant bacteriuria belonged to the low socioeconomic group. Unlike in previous studies in this country, the most prevalent organism in this study was the Staphylococcus aureus. In view of the high incidence of the problem in this environment, it is important that routine screening of urine for significant bacteriuria should be part of our ante-natal clinic services at least on the first visit of pregnant women to ante-natal clinics.

Asymptomatic significant bacteriuria among pregnant and non-pregnant women in Sagam, Nigeria.

In a study carried out among 510 pregnant and 304 non-pregnant women at Ogun State University Teaching Hospital, Sagamu, 122 (23.9 pc) of the pregnant women and 37 (2.2 pc) of the non-pregnant women had significant bacteriuria. The rate amongst the pregnant women was significantly higher than in non-pregnant women (P < 0.001). There was a correlation between pyuria and significant bacteriuria in 45 (8.8 pc) of the pregnant women and in 11 (3.6 pc) of the non-pregnant women. Significant bacteriuria was closely associated with nulliparae. Most of the pregnant women with significant bacteriuria belonged to the low socio-economic group. Unlike in previous studies in this country, the most prevalent organism in this study was the Staphylococcus aureus.

Carriage of Staphylococcus aureus among hospital personnel in a Nigerian hospital environment.

Among the 395 hospital staff examined during this study, 35.2pc of them were found to carry S. aureus in their anterior nares. The carriage was slightly higher in females (35.8pc) compared with 34.4pc in males, although it was not statistically significant. When the different age groups and professions were considered, the carriage was highest among the age group of 21-30 years and with the Nursing staff, who incidentally, are closest to the patients and had the highest number among the staff members examined. The carrier rate was also significantly higher (P less than 0.05) among staff members who had worked in the hospital for 7-10 months compared with other staff. There was a good correlation (97pc) between coagulase positivity and mannitol fermentation, while Methicillin, Claforan and Gentamycin were found to be very effective against most of the isolates. On re-examination of those staff members who ar closely associated with the patients two years after the initial exercise in 1987, it was evident that a significant number (P less than 0.05) of those carriers of Staph aureus in our hospital are not persistent ones.