Potentially zoonotic shiga toxin-producing Escherichia coli serogroups in the faeces and meat of food-producing animals in Ibadan, Nigeria

Shiga toxin-producing Escherichia coli (STEC) are major food-borne pathogens associated with gastroenteritis and sometimes fatal haemolytic uraemic syndrome complication. Farm animals are asymptomatic carriers of STEC and contaminated meat is an important vehicle for zoonotic transmission from animals to humans. This study investigated the presence, virulence traits and antimicrobial susceptibility of seven potentially human pathogenic STEC serogroups (O157, O26, O91, O103, O111, O128 and O145) in the faeces and meat of food-producing animals in Ibadan, Nigeria. One hundred and fifty-four (7.3%) of 2133 samples were positive for STEC serogroups. The pathogens were detected in the faeces of cattle (15.2%), sheep (10.7%), goats (7.5%) and pigs (5.6%) as well as in beef (3.8%), goat-meat (1.7%) and pork (4.0%). All seven investigated STEC serogroups were found in cattle, all except O145 were found in sheep, three serogroups (O157, O26 and O111) were found in goats and three (O157, O111 and O128) in pigs. The rate of detection of each of the serogroups in all 2133 samples was: O157 (5.0%), O26 (0.2%), O91 (0.3%), O103 (0.3%), O111 (1.0%), O128 (0.2%) and O145 (0.1%). Of all 154 isolates, 11.0% had shiga toxin type 1 gene (stx(1)), 25.3% had stx(2) and 41.6% had stx(1)/stx(2); intimin gene (eaeA) was detected in 56.5% and enterohaemolysin gene (hlyA) in 75.3%. Among the O157 isolates, 24.5% were negative for stx genes but positive for eaeA and/or hlyA while 7.6% were negative for all four virulence genes. Fourteen different combinations of virulence genes were encountered but stx(1)/stx(2)/eaeA/hlyA combination was the most predominant. The percentage resistance of the isolates to the tested antimicrobial agents was: ampicillin (82.5%), chloramphenicol (42.9%), ciprofloxacin (22.1%), enrofloxacin (25.3%), nalidixic acid (37.7%), neomycin (24.0%), norfloxacin (20.8%), streptomycin (50.7%) and tetracycline (75.3%). One hundred and forty-eight (96.1%) of all 154 isolates were resistant to at least one of the tested antimicrobial agents while 69.5% were categorised as multi-drug resistant. Potentially pathogenic multi-drug resistant STEC isolates were recovered from the meat production chain in Nigeria. Unhygienic practices that predominate during slaughter and processing were observed to have contributed to faecal contamination and presence of STEC in meat.

Polymerase chain reaction assay of ureaplasma strains isolated from high vaginal swabs of women in Ibadan, Nigeria

Human ureaplasma previously had one species known as Ureaplasma urealyticum but was recently separated into 2 species, U. urealyticum and U. parvum. This study was carried out to separate the ureaplasma strains isolated from women attending a tertiary-care hospital in Nigeria. Thirty (30) Ureaplasma strains isolated from the vaginal tracts of 13 pregnant and 17 non-pregnant women were assayed. The polymerase chain reaction (PCR) technique was employed using two primer pairs: UMS-170/UMA-263 specific for U. urealyticum and UMS-57/UMA-222 specific for U. parvum. The positivity bands of the primer pairs were 476 bp and 326 bp for U. urealyticum and U. parvum respectively. All isolates were found to be U. urealyticumn (100%). Eleven (84.6%) of the 13 U. urealyticum from pregnant women were from asymptomatic women while from the non-pregnant women; 6 (35.3%) were from women with complaint of infertility problems; 5 (29.4%) from those who complained of vaginal discharge, one (5.9%) was asymptomatic while the remaining 5 (29.4%) had various other complaints. U. urealyticum is thus the prevalent species of Ureaplasma among pregnant and non-pregnant women in the study population and this to the best of our knowledge is a pioneer study to speciate human ureaplasmas in this country.

Genital mycoplasmas in semen samples of males attending a tertiary care hospital in Nigeria: any role in sperm count reduction?

Semen samples from 54 married men attending the outpatient clinics for problems of infertility and routine semen analysis were examined for the presence of genital mycoplasmas. The mean age of the men was 36.1 years with a range of 25 55 years. Majority of the men 57.4% (31 of 54) were in their fourth decade of life (30 39 years). This age group also had the highest percentage 57.2% (8 of 14) of positive isolates of genital mycoplasmas on semen culture. A total of 21 organisms obtained from 14 (26.0%) positive samples were isolated. Mycoplasma and Ureaplasma spp. separately isolated from the samples yielded frequencies of 1 (1.9%) and 6 (11.1%) respectively and the remaining 7 (13.0%) samples were infected with both organisms. A breakdown of the mycoplasma species include 5 (23.8%) M. hominis, 2 (9.5%) M. fermentans and 1 (4.8%) M. penetrans. Apart from one isolate of M. hominis other Mycoplasma species were found in association with Ureaplasma species. Fifteen (71.4%) of the 21 isolates [8 (53.3%) ureaplasmas and 7 (46.7%) mycoplasmas] were isolated from samples with sperm counts less than 20 million/ml while the remaining 6 (21.6%) isolates [5 (83.3%) ureaplasmas and 1 (16.7) mycoplasma] were from samples with counts greater than 20 million/ml. This finding could indicate a possible influence of genital mycoplasmas especially mycoplasmas species on sperm count.

Presence of mycoplasma and ureaplasma species in the vagina of women of reproductive age

OBJECTIVE

Against the background of genital mycoplasmas being implicated as pathogens in the genital tracts of adult humans, this study was carried out to determine the prevalence of genital mycoplasmas among women of reproductive age attending a tertiary-care hospital in Nigeria.

METHODS

One hundred and sixty-eight high vaginal specimens from 114 pregnant and 54 non-pregnant women with or without complaints were studied for the presence of genital mycoplasmas using selective bacteriological culture techniques. Isolates were identified biochemically and serologically.

RESULTS

Sixty (35.7 %) isolates of genital mycoplasmas were obtained from the study population. Identification showed 30 (17.9%) as Mycoplasma species, 13(7.7%) as Ureaplasma species and 17(10.1%) were positive for both organisms. Thirteen (11.4%) ureaplasma isolates were from pregnant women and 17 (31.5%) from non-pregnant women (p< 0.05). Thirty-eight (80.8%) of the Mycoplasma species were identified as Mycoplasma hominis, 6(12.8%) as M.fermentans and 3(6.4%) as M. penetrans. High prevalence of the Mycoplasma species were obtained from asymptomatic pregnant women (84.8%) while the Ureaplasma species were found more from symptomatic non-pregnant women- 35.3 % from infertility patients, 29.4% from those with vaginal discharge and 29.4% from those with other gynaecological complaints.

CONCLUSION

These findings could be important since genital mycoplasmas have been associated with various adverse conditions especially in pregnant women and neonates while Ureaplasma species have been implicated in infertility. Their specific roles need further investigations.

Biochemical and serological characterization of mycoplasma strains isolated from the genital tracts of humans in Nigeria

Fifty-five (55) Mycoplasma strains isolated from the genital tracts of humans were biochemically characterized using various biochemical tests and also serologically identified by growth inhibition technique using 5 mycoplasma antisera namely M. hominis PG2 1: M. genitalium G37: M. penetrans GTU54 and 2 strains of M. fermentans PG18 (HRC 6-62-S-170 and MB713-501-069). Biochemically, 43 (78.2%) strains were identified as Mycoplasma hominis, 8 (14.5%) strains as M. fermentans and 4 (7.3%) as M. penetrans. The M. hominis strains hydrolyzed only arginine while the M. fermentans and M. penetrans strains in addition to arginine hydrolysis also broke down glucose fermentatively and oxidatively. The M. fermentans strains showed varying reactions to phosphatase activity and to the reduction of tetrazolium chloride. Serologically, 4 (7.3%) mycoplasma strains were confirmed as M. penetrans GTU54 and of the 8 M. fermentans strains, 4 (7.3%) were identified as M. fermentans PG18 serotype HRC 6-62-S-170 and the other 4 (7.3%) as M. fermentans PG18 serotype MB 713-501-069. Only 13 (30.2%) of the 43 M. hominis strains were identified as M. hominis serotype PG2 1. None was identified as M. genitalium. The heterogeneity of the mycoplasma strains especially M. hominis was observed in this study and the need for the use of multiple antisera in growth inhibition test is hereby supported.

Enterotoxigenicity and drug sensitivity of staphylococci from children aged five years and below with sporadic diarrhoea

OBJECTIVE

To investigate the incidence of enterotoxigenic strains of staphylococci in children aged five years and below suffering from sporadic diarrhoea and their antibiotic susceptibility pattern.

DESIGN

Collection of stool samples from children with sporadic diarrhoea and laboratory based microbiological analysis.

SETTING

Microbiology Research Laboratory, Department of Veterinary Microbiology and Parasitology, University of Ibadan, Ibadan, Nigeria.

RESULTS

Out of one thousand seven hundred and sixty one diarhoeic faecal specimens collected, one hundred and seven strains of staphylococci were isolated as pure culture. Seventy two of these 107 staphylococci were coagulase positive S. aureus, 33 strains were S. epidermidis and two strains were S. saprophyticus. Sixty one (84.7%) of 72 isolates of S. aureus produced enterotoxins. Staphylococcal enterotoxins A was produced singly by 37(60.7%) of the toxigenic strain, while 12(19.7%) produced enterotoxin D alone. Two strains produced both enterotoxins A and C, six strains produced both enterotoxins A and D, one strain produced enterotoxins A, C and D while two strains produced enterotoxins A, B, and D. Most strains were resistant to pennicilin, with minimum inhibitory concentrations (MIC) within the range of 1-16 microg/ml.

CONCLUSION

Enterotoxigenic strains of S. aureus were recovered from children aged five years and below suffering from sporadic diarhoea. The incidence rate was 3.5% of the samples investigated. Results of their antibiogram revealed that chloramphenicol, gentamicin, cephalothin and clindamycin would be appropriate for treatment of such diarrhoea after the clinical value of the antibiotics in young children has been evaluated.

Plasmid profiles of Shigella and Salmonella spp. isolated from diarrhoeic humans in Ibadan, Nigeria

Clinical isolates of Shigella flexneri, S. dysentariae, S. boydii and Salmonella spp. were screened for the presence of plasmids. Most of the isolates harboured more than one plasmid ranging in molecular size from 1.3 to 36.1 x 10(6) daltons. Very large plasmids were not encountered.

Antimicrobial resistance patterns and plasmid survey of Salmonella and Shigella isolated in Ibadan, Nigeria

Antibiotic resistance patterns among Salmonella and Shigella spp isolated from diarrhoeic human beings were studied. Eleven antibiotic resistance patterns were observed. Plasmid survey of the isolates revealed the presence of multiple plasmids in thirty two of the fifty three strains. More plasmid patterns than antibiotic resistance were observed. Incidence of Salmonellosis and Shigellosis in this environment is caused by genetically unrelated Salmonella and Shigella strains although with identical drug resistance patterns.

Transmissible drug resistance among Shigellae and other enterobacteriaceae isolated from diarrhoeic human beings in Ibadan, Nigeria

Antibiotic resistance patterns and the distribution of R-factors among Shigella, Salmonella and Escherichia coli isolated from diarrhoeic human beings were studied. Nine multiple antibiotic resistance patterns among which PNS TCK was the most common were observed. All the Shigella, Salmonella and eighteen Escherichia coli isolates transferred part of their r determinants respectively to E. coli K12. It is thought that enforcement of the law regulating the sales and judicious use of antibiotic in Human and Veterinary Medicines would reduce the incidence of multiple drug resistance in Nigeria.

Determination of asymptomatic carrier rate of beta-haemolytic group B Streptococcus in vaginas of pregnant women in Ibadan, Nigeria

Bacteriological studies of 500 vaginal swabs from pregnant women in second and third trimester from 4 government hospitals in Ibadan showed that 8 (1.6 per cent) were found to be culture-positive for Group B Streptococcus. Five (1.0 per cent) were found to harbour group D streptococci. All the 8 group B Streptococcus isolates were sensitive to erythromycin, methicillin, penicillin G, ampicillin and chloramphenicol in decreasing order. They were resistant to tetracycline, sulphafurazole and streptomycin.

Escherichia coli O:K:H: serotypes in urinary tract infection

Of 70 E. coli isolates from urinary tract infection 44 isolates were groupable with the 164 O antisera. The most predominant O groups were O21, O6, O2, O8, and O15. Twenty four of the isolates had K antigens of which K3 occurring in E. coli O21 was most common. Sixty five of the isolates were resistant to ampicillin, chloramphenicol, streptomycin, septrin and oxytetracycline or a combination thereof. It is suggested that ampicillin, chloramphenicol and oxytetracycline should be used judiciously and on the advice of a medical practitioner to reduce the incidence of drug resistance and R-factor.

Transmissible drug resistance in human and animal trains of Enterobacteriaceae and Pseudomonas aeruginosa

In an investigation carried out over a period of six months, 53 strains of Enterobacteriaceae and nine strains of Pseudomonas aeruginosa were examined for antibiotic resistance and transmissible drug resistance factor. Seventeen antibiotic resistance patterns were found among 51 drug resistant Enterobacteriaceae. Of the 62 strains, 23 were capable of transferring a part or all of the antibiotic resistance pattern to sensitive Escherichia coli. The P aeruginosa isolated from both man and piglets harboured R-factors which were transferable at high frequencies to the sensitive recipients, while only one of the six single resistant E coli isolated from piglets transferred resistance to the sensitive recipients. The minimum inhibitory concentrations of oxytetracycline, ampicillin, chloramphenicol, sulphadimidine and streptomycin of the resistant E coli, P aeruginosa, Salmonella spp and Proteus spp were 500 to 625, 62 to 500, 500 to 625, 500 and 7.8 to 500 micrograms/ml, respectively.

Infectious drug resistance in E. coli isolated from livestock

Escherichia coli strains isolated from clinically healthy and sick animals in Lagos and Oyo States of Nigeria were tested for drug resistance and distribution of R-factors. Fifteen multiple and 3 single (OT, S, S3) antibiotic resistance patterns were obtained among 333 isolates. Of the 285 resistant strains, 133 transfered their resistant determinant to sensitive E. coli K 12 recipients in part or as a block. None of the donors had sex pili and they were not lysed by Ms2 phage. It required about 2 h for E. coli K 12 to acquire a resistance determinant from E. coli strains Nos. 295, 62 and 67 habouring resistance to oxytetracycline, streptomycin and compound of sulphonamides (S3). The number of recipient cells that formed transconjugants increased with the time of incubation.

Dermatophytosis survey in Lagos State of Nigeria

A dermaphytosis survey covering 3,860 schoolchildren was conducted in Lagos, Nigeria, between January 1973 and January 1974. Seven species of dermatophytes, namely, Trichophyton mentagrophytes (four isolates), T. rubrum (three isolates), T. soundanense (11 isolates), Microsporum canis (five isolates), M. gypseum (two isolates), M audouinii (four isolates), and Epidermophyton floccosum (three isolates) were recovered from specimens collected from the hair, skin and scalp scrapings of 81 schoolchildren. The incidence of dermatophytosis (2.10%) is low in schoolchildren covered in this survey. This is the first time M. canis and M. Gypseum have been isolated from superficial skin lesions in human beings in Nigeria.

Preliminary report on measurement of immunoglobulin IgG in Nigerian patients with dermatomyphytosis

Thirty non-atopic adult Nigerian patients, with dermatophytosis, who showed no other demonstrable abnormality, and who denied any family history of atopy were studied for serum levels of immunoglobulin IgG. The results of serum gamma G. Immunoglobulin concentrations, as measured by the formation of precipitant rings using the Hyland technique in these patients, when compared with those in two control subjects and three other patients with trichophytide reactions, clearly showed much higher concentrations of IgG class of immunoglobulin in dermatophytosis. This finding thus supports an immunological role, as has been postulated by other investigators, in the pathogenosis of this disease. The high levels of this immunoglobulin in some of these patients calls for further study. Possible hypotheses are given. The serum levels of IgE levels of patients with "Ide Reaction" needs to be measured. The Hyland Immunoplate technique method of quantitation of immunoglobulins is described. The practising allergist can now measure most immunoglobulins.