Yeast associated with human infections in south-eastern Nigeria.

A total of 1921 specimens from nine clinical sources were examined by direct microscopy and culture to recover yeast associated with human infection. Identification of yeast was based on their carbon assimilation patterns, using API 20C AUX and ID 32 C (bioMérieux, France) commercial kits. A total of 178 specimens (9.3%) were positive for yeast. Most of the yeast isolates were recovered from urine samples and genital swabs. Prevalence was significantly higher in women (14.7%) than in men (1.4%) (P < 0.05). The age group 21-30 years recorded the highest prevalence of yeast infection (65.2%) followed by age group 11-20 years (16.9%) and > 40 years (9.0%). When genital samples were considered, prevalence was significantly higher in the age group 21-30 years than that in older ones (P < 0.05). Isolates recovered included seven species of Candida and Trichosporon inkin. C. albicans accounted for the highest number of isolates (128) followed by C. tropicalis (23) and C. parapsilosis (9). Two isolates each of C. famata and C. norvegensis were recorded and are reported for the first time in Nigeria. The two isolates of T. inkin were recovered from perianal lesions and are also reported for the first time from Nigeria. C. albicans, C. glabrata, C. parapsilosis and C. krusei were found to be the most common yeast species that act as agents of human disease in south-eastern Nigeria.

Faecal excretion of Vibrio cholerae during convalescence of cholera patients in Calabar, Nigeria.

The pattern of faecal excretion of Vibrio cholerae was studied over a duration of eight months among 13 cholera convalescents by two-weekly surveillance cultures. Stools and rectal swabs were cultured on Thiosulphate citrate bile salts sucrose (TCBS) agar for the recovery of vibrio pathogens. Clinical phase and convalescent phase V. cholerae strains were compared for antibiogram profiles. The population of vibrios recovered from faecal inocula was usually scanty (<10(3) vibrios/g). All clinical isolates except three were concordant with convalescent phase strains. Sensitivity to tetracycline was uniform for concordant V. cholerae strains, with minimum inhibitory concentration (MIC) ranging from 0.54-4.0 microg/ml. Nine (69.2%) of the convalescents had positive faecal cultures for periods ranging from two weeks to more than seven months. Two adults whose excretions lasted several months also tested positive for human immuno-deficiency virus (HIV) infections. The significance of stool surveillance cultures for identifying asymptomatic infections among convalescents who may need chemotherapy to abolish excretion is emphasised. However, it could not be established with certainty if vibrios excreted during convalescence were from enteric colonization by the causative strains, or re-infections with the common strains in circulation.

Internalization of Escherichia coli by human renal epithelial cells is associated with tyrosine phosphorylation of specific host cell proteins.

Human renal epithelial cells are capable of internalizing Escherichia coli regardless of whether the bacteria are isolated from individuals with pyelonephritis or from healthy volunteers. In this study, we investigated the role of host cell tyrosine kinase activity in internalization. We found that internalization of both fecal and pyelonephritis isolates is blocked by tyrosine kinase inhibitors. We found increased intensity of two tyrosine-phosphorylated proteins, with relative mobilities of approximately 123,000 and 110,000, in Western blots of extracts from human renal epithelial cells infected with E. coli. The increased intensity of these tyrosine-phosphorylated proteins was observed only in the Triton X-100-insoluble fraction, suggesting that these proteins could be associated with the cytoskeleton. Increased tyrosine phosphorylation of these proteins upon E. coli infection was observed in both transformed and primary human renal epithelial cells and in cells infected with several different strains of E. coli isolated from the feces of healthy individuals or from the blood or urine of patients with pyelonephritis. The increased tyrosine phosphorylation of these proteins required live bacteria and was blocked by tyrosine kinase inhibition but not by protein synthesis inhibitors or cytochalasin D. These experiments establish a strong link between E. coli internalization and host cell signaling through tyrosine kinases in human kidney cells and provide evidence that specific proteins are involved in these processes.

Aeromonads in acute diarrhoea and asymptomatic infections in Nigerian children.

Stool samples of 616 asymptomatic and 296 diarrhoeic school children were compared for the recovery rate of Aeromonas spp. on ampicillin (10 micrograms/ml) sheep blood agar. Culture filtrates of isolates were tested for haemolysin production with 1% freshly washed rabbit erythrocytes. Stools of 9 (3.0%) diarrhoeic children yielded five strains of A. hydrophila and four of A. veronii (two each of biotypes sobria and veronii), compared to 12 (1.9%) (p > 0.01) asymptomatic children who harbored seven A. hydrophila and five A. caviae strains. Isolates from-diarrhoeic stools were exclusively from children < or = 5 years, while all infected asymptomatic children were > or = 6 years. Culture filtrates of all nine diarrhoeic strains were uniformly enterotoxigenic (intestinal weight ratio > 0.083) and produced haemolysin titres > 128. These phenotypes where variable in carriage strains of A. hydrophila but were not detected in A. caviae. The recovery of A. hydrophila, and A. veronii biotypes from diarrhoeic stools of children < or = 5 years may suggest their involvement in diarrhoea causation in the absence of other diarrhoeagenic agents.

Binding to and killing of human renal epithelial cells by hemolytic P-fimbriated E. coli.

Acute pyelonephritis is a common invasive infection frequently caused by E. coli that possess P-fimbriae and secrete hemolysin. We have examined the role of P fimbriae and hemolysin in the killing of putative target cells of acute pyelonephritis, that is, human renal epithelial cells (HRPTEC). Cultures of HRPTEC were overlaid with (1) a prototypic pyelonephritogenic E. coli (CFT073) which expresses both P fimbriae and hemolysin; (2) its hemolysin-negative isogenic mutant (CFT073hlyD::TnphoA); or (3) a prototypic nonpyelonephritogenic fecal E. coli (FN414) which is negative for both P fimbriae and hemolysin. CFT073 and CFT073hlyD::TnphoA but not FN414 adhered to HRPTEC, as demonstrated by electron microscopy and direct counting. Adherence was diminished by antisera directed against P fimbriae and by a monoclonal antibody recognizing the epithelial receptor for P fimbriae. CFT073 was significantly more cytolethal for HRPTEC than its hemolysin-negative mutant. The bacteria-free filtrate of CFT073 was both hemolytic and cytolethal whereas that of CFT073hyD::TnphoA was not hemolytic and was significantly less cytolethal. Finally, we demonstrated that CFT073 passed through monolayers of HRPTEC at a higher rate than CFT073hlyD::TnphoA, indicating that hemolysin damages HRPTEC, facilitating passage of bacteria through the epithelial barrier. With HRPTEC and a pyelonephritogenic strain of E. coli we have reproduced in vitro bacterial attachment and toxin delivery by P fimbriae and hemolysin, factors epidemiologically associated with acute pyelonephritis in patients.

Internalization of Escherichia coli into human kidney epithelial cells: comparison of fecal and pyelonephritis-associated strains.

A gentamicin survival assay, using primary human renal epithelial cells and Escherichia coli strains isolated from the feces of asymptomatic individuals and from the urine or blood of patients with acute pyelonephritis, was used to investigate bacterial internalization as a model for renal parenchymal invasion in pyelonephritis. E. coli strains, regardless of their origin, efficiently entered into human renal epithelial cells, a process inhibited by cytochalasin D. While the percentage of survival of nonhemolytic pyelonephritis isolates did not differ from that of fecal isolates, survival of hemolytic pyelonephritis strains was lower than that of nonhemolytic strains, perhaps as a consequence of the greater cytotoxicity of hemolytic strains. There was no evidence of intracellular multiplication of E. coli. These results demonstrate that human renal epithelial cells are capable of efficient uptake of E. coli regardless of the source of the bacteria.

Bacterial agents in neonatal septicaemia in Calabar, Nigeria (a review of 100 cases).

This study of bacterial isolates in 100 cases of proven neonatal septicaemia has shown Staphylococcus aureus and coliform bacterials the dominant gram positive and gram negative organisms respectively. Most gram negative bacteria and Staphylococcus aureus were sensitive to gentamycin, while streptococci were sensitive to ampicillin. On the basis of this antimicrobial sensitivity pattern, we recommend the use of gentamycin and ampicillin as initial antibiotics in neonatal septicaemia.

Features of cholera and Vibrio parahaemolyticus diarrhoea endemicity in Calabar, Nigeria.

The clinical and epidemiological features of acute vibrio diarrhoeal disease were studied in 881 patients seen at the University of Calabar Teaching Hospital (UCTH), Calabar, Nigeria, between January and December 1989. Stools and rectal swabs of patients and randomly-selected control subjects were microscopically and culturally examined for the presence of enteric pathogens. Households of vibrio diarrhoea cases and matched controls were visited for ecologic studies. Of a total of 108 (12.3%) culturally-confirmed bacterial diarrhoeas, 47 (43.5%) were due to Escherichia coli, 33 (30.6%) to Vibrio cholerae-01 (classical and El Tor biotypes) and V. parahaemolyticus, while shigellae and salmonellae accounted for 29 (26.9%) and 9 (8.3%) cases, respectively. Most cholera case households clustered within the ancient neighbourhood of the inner city, characterized by poorly developed water and sewage disposal systems. A preponderance of vibrio diarrhoea patients were children < or = 10 years. Adult cases involved mostly females. The only case of diarrhoea-related death involved an eight-month old child with kwashiorkor and V. parahaemolyticus infection. Incidence of vibrio diarrhoeas was seasonal, with most cases occurring during the dry season followed by subsidence at the onset of rainy season. Bimodal peaks of vibrio diarrhoeal episodes observed over the period appeared to coincide with periods of acute water scarcity, high temperature, increased fishing activities and trade traffic on the Calabar River estuary. Of the environments sampled, only clam shells from a case household and river sediments yielded vibrio pathogens on culture. Ecological factors that are capable of stabilizing a focus of vibrio diarrhoea endemicity in this area are highlighted.

Dermatomycoses among industrial workers in Cross River State, Nigeria.

A survey of dermatomycoses was carried out amongst industrial workers in three different factories during the period 1987-1988. A total of 194 workers were screened, out of which 54 proved to be mycologically positive by microscopy and/or culture. Incidence was apparently highest amongst workers in a cement factory (Calcemco, 33.3%) followed by those in a wood factory (Seromwood, 30.8%) and a rubber factory (CREL, 26.2%). Pityriasis versicolor was the predominant clinical type of dermatomycosis, followed by tinea pedis. A total of 51 fungal organisms were identified. Malassezia furfur was the most prevalent causative agent (74.4%) followed by Trichophyton soudanense (5.8%), T. rubrum (3.9%) and Epidermophyton floccosum (3.9%). Other species identified were one isolate each of T. tonsurans, T. mentagrophytes, T. verrucosum, Candida tropicalis, Candida spec. and Geotrichum candidum.

Septicaemia among neonates with tetanus.

In a study of 149 cases of neonatal tetanus (NNT) admitted into the University of Calabar Teaching Hospital, 49 (33 per cent) were also found to have septicaemia. The dominant organisms were coliforms and Staphylococcus aureus. A comparison of the clinical features of the septicaemic and non-septicaemic neonates showed umbilical cord infection to be an indicator of septicaemia. There was no significant difference in the case fatality rates of the two groups of patients and the overall case fatality was low (37 per cent). This is attributable to early diagnosis and treatment of the septicaemia cases. It is suggested that paediatricians should have a high index of suspicion of septicaemia among cases of NNT as a means of reducing case fatality.

Neonatal septicaemia in Calabar, Nigeria.

In a twelve-month prospective study of 132 neonates suspected of having septicaemia in the Special Care Babies Unit (SCBU) of the University of Calabar Teaching Hospital (UCTH), Calabar, 79 were confirmed by positive blood cultures. Forty (50.6 pc) of these were preterm infants. The incidence was 19.3 per 1,000 hospital live births, while the mortality rate was 30.3 pc. The main predisposing factors were birth asphyxia, birth outside hospital, prolonged rupture of membranes, prolonged labour and poor water supply in hospital. The predominant pathogens were coliform organism and Staphylococcus aureus. The antibiotic sensitivity pattern of the pathogens suggest the use of gentamicin as a sole agent in the initial treatment of septicaemia while awaiting culture results. In view of the role of inadequate antenatal care, poor water supply and unhygienic delivery practices in the aetiology of newborn septicaemia, it is suggested that improved antenatal care, water supply and childbirth practices will reduce the incidence of septicaemia.

Penicillinase-producing Neisseria gonorrhoeae conjunctivitis on some Nigerian children.

During 21 month study of bacterial conjunctivitis among 121 children in two health care centres in Calabar, Nigeria, a total of 90 (74.4%) cases were culturally confirmed. Neonates had the highest age-specific attack rates with 48 (53.3%) cases. Neisseria gonorrhoeae, the predominant pathogen, was recovered from 32 (35.6%) infections; 21 (65.6%) of them from neonates. Cultures of genital swabs of consenting parents of infected neonates as well as those of three female children aged 2-12 years with concurrent vulvo-vaginitis yielded N. gonorrhoeae. Younger women, mostly primi-gravidae were more frequently found to have benefited from peri-natal health care services than older multi-gravidae. Nevertheless, such access to health care services did not appear to influence the frequency of gonococcal conjunctivitis in neonates from the two maternal groups (P < 0.01). Sexual abuse and contaminated fomites were the possible modes of gonococcal infection transmission to older children. Overall, 22 (68.8%) strains of gonococci were resistant to penicillin; 19 (59.4%) were penicillinase-producing Neisseria gonorrhoeae (PPNG), while 5 (15.6%) had chromosomally-mediated resistance. All isolates were sensitive to erythromycin. This study recommends a review of gonorrhoea surveillance in pregnancy to include routine examination of cervical swabs just before delivery.

Antimicrobial resistance trends of shigellae isolates from Calabar, Nigeria.

During a 3-year study (January 1986-December 1988), stools of 2200 diarrhoeal or dysenteric patients were examined by culturing and 108 (4.9%) were found positive for shigellae. Shigella flexneri was the commonest species isolated (54.6%), followed by Sh. dysenteriae (24.1%). Patients aged less than or equal to 15 years accounted for 51.4% of cases. Shigellae over the 3 years showed high and sometimes rising resistance to ampicillin, chloramphenicol, streptomycin and cotrimoxazole and complete resistance to tetracyclines and sulphonamides. Sh. sonnei strains isolated in 1986 and 1987 were almost invariably sensitive to all antimicrobial agents except ampicillin, while in 1988 strains were resistant to all. The isolation rate was higher (74.1%) during the dry season than in the rainy season (25.9%) (P less than 0.01). Low standards of community and personal hygiene and improper sewage disposal are the prevailing epidemiological factors identified.

Bacterial agents in neonatal septicaemia in Calabar, Nigeria: review of 100 cases.

This study of bacterial isolates in 100 cases of proven neonatal septicaemia has shown Staphylococcus aureus and coliform bacteria as the dominant Gram-positive and Gram-negative organisms respectively. Most Gram-negative bacteria and Staphylococcus aureus were sensitive to gentamicin, while streptococci were sensitive to ampicillin and penicillin. On the basis of this antimicrobial sensitivity pattern, the combination of gentamicin with either ampicillin or penicillin appears appropriate in initial therapy of neonatal septicaemia.

Occurrence of Plesiomonas shigelloides--associated diarrhoea in Calabar, Nigeria.

The prevalence, clinical profiles and virulence factors of Plesiomonas shigelloides were determined in patients attending the University of Calabar Teaching Hospital, Microbiology Laboratory. P. shigelloides was isolated from 12 (1.4%) of 880 patients with diarrhoea and from none of the controls (P less than 0.05). Isolates were mostly from febrile children less than or equal to 10 years with most of the infections occurring during the rainy months. Although our findings suggest the significance of Plesiomonas in acute diarrhoea in this environment, our isolates did not seem to show any of the proxy indicators of virulence usually associated with other enteric pathogens.

Cholera and Vibrio parahaemolyticus diarrhoea endemicity in Calabar, Nigeria.

The microbiological and morbidity profiles of acute diarrhoeal episodes were studied in 881 patients seen at the Out-Patients Department of the University of Calabar Teaching Hospital (UCTH), Calabar, between January and December, 1988. Of a total of 108 (12.3%) culturally confirmed bacterial diarrhoeas, 47 (43.5%) were due to Escherichia coli, 33 (30.6%) to vibrios (Vibrio cholerae-01; classical and E1 Tor biotypes and V. parahaemolyticus), while shigella spp. and salmonella. spp. accounted for 29 (17.7%) and 9 (8.3%) episodes respectively. Twenty (64.5%) of the patients with vibrio diarrhoeas were children less than or equal to 10 years. The only case of diarrhoea-associated death observed, involved an 8-month old infant with kwashiorkor and V. parahaemolyticus infection. Bimodal peaks of cholera episodes occurred during the dry season and appeared to coincide with acute water shortage periods in the municipality. The significance of some prevailing ecological factors in stabilizing a focus of cholera and halophilic vibrio diarrhoea endemicity in this region is discussed.

Pityriasis versicolor in school children in Cross River State of Nigeria.

Out of 2,353 primary school children aged 4-16 years in Cross River State of Nigeria examined, 88 (3.7%) showed lesions mycologically proven to be pityriasis versicolor. Incidence was highest (6.3%) in children aged 12-16. Lesions were much more common on the face than on other sites.

Home medication and microbiological profile in chronic otitis media in some Nigerian children.

The relationship of home medication to the pathology and microbiological profiles of chronic otitis media was studied in 135 children with middle ear infections. Middle ear lesions were examined and sample obtained for microscopy and culture for bacterial and fungal pathogens. Of a total 115 patients who received home treatment, mostly with extracts of a local herb, Cleome ciliata and unprescribed antibiotics, 111 (96.5 pc) had chronic otitis media with purulent effusion (OME), compared with 11 (55 pc) otitis media (OM) cases among 20 patients who had not received such treatments (p less than 0.05). Staphylococcus aureus and Pseudomonas spp. were the predominant isolates; the latter were the sole infecting agents in 41 episodes and occurred in 10 co-infections. Sensitivity pattern of bacterial isolates indicated that a large proportion of infections would respond to empiric treatment with gentamicin in anticipation of laboratory results on sensitivity tests. This report suggests further studies to define the significance of these medications in the pathogenesis of chronic OME in Nigerian children.

Comparative study of the prevalence and clinical profiles of diarrheas due to Aeromonas and other enteric pathogens.

The prevalence of Aeromonas spp. and other enteric pathogens in stool specimens from diarrheic and non-diarrheic patients was studied over a 12 month period (January to December, 1986). Except for the absence of fever, all the clinical features in Aeromonas diarrhea were comparable to those associated with other diarrheagenic agents. These features included abdominal pain (30%), vomiting (24.5%), fever (31.5%), dehydration (9.5%) and hematochezia (19.5%). Aeromonas spp. were more frequently isolated from patients with gastroenteritis (2.5%) than from control patients (1.0%) (P less than 0.05). Isolates were recovered more often during the dry months (66.7%), than during the wet months (33.3%). Among the enteric pathogens isolated, Aeromonas spp. (2.5%) ranked next to Esch. coli (14.5%) and Shigella spp. (6.3%) in prevalence. Other bacterial isolates included Plesiomonas shigelloides (1.5%) Vibrio spp. (1.0%), Yersinia enterocolitica (1.0%) and Salmonella spp. (1.8%).