Molecular typing of Candida albicans isolates from patients and health care workers in a neonatal intensive care unit

AIMS

The aim of this study was to investigate the genetic relatedness between Candida albicans isolates and to assess their nosocomial origin and the likeliness of cross-transmission between health care workers (HCWs) and hospitalized neonates in a neonatal intensive care unit (NICU).

METHODS

We retrospectively analysed 82 isolates obtained from 40 neonates and seven isolates from onychomycosis of the fingers of five HCWs in a Tunisian NICU by using pulsed-field gel electrophoresis (PFGE) and randomly amplified polymorphic DNA (RAPD) analysis with CA1 and CA2 as primers.

RESULTS

In RAPD analysis, the discriminatory power (DP) of CA1 and CA2 primers was 0·86 and 0·81, respectively. A higher DP was achieved by combining patterns generated by both primers (0·92), while PFGE karyotyping exhibited the lowest DP (0·62). The RAPD-CA1/CA2 analysis revealed that 65·8% of isolates obtained from neonates derived from a limited number (6) of groups of genetically identical strains, that five temporal clusterings occurred during the study period and that three HCWs' isolates and 11 isolates obtained from six neonates were identical.

CONCLUSIONS

These findings argue for the nosocomial transmission of C. albicans in our NICU and for the transfer of strains from HCWs to patients.

SIGNIFICANCE AND IMPACT OF THE STUDY

Identification of relatedness between Candida species obtained from neonates and health care workers by using molecular techniques with high discriminatory power is essential for setting up specific control measures in order to reduce the incidence of nosocomial candidiasis.

Phylogeography of Androctonus species (Scorpiones: Buthidae) in Tunisia: Diagnostic characters for linking species to scorpionism

A fragment of the mitochondrial (mt) 16S ribosomal RNA gene was amplified by PCR and sequenced from individual adult scorpions of the genus Androctonus, which were sampled from central and southern Tunisia and identified using an explicit set of morphological characters. Phylogenetic analyses placed the mtDNA haplotypes in three well-supported monophyletic lineages, corresponding to the morphospecies Androctonusaeneas, Androctonusamoreuxi and Androctonusaustralis. The latter species was the most abundant and widespread, and it was characterized by two mtDNA sub-lineages each of which predominated only north or south of the Chott el Jerid, a seasonally flooded saline depression that divides non-Mediterranean Tunisia. The divergence of the two mtDNA lineages was dated by mtDNA molecular clocks, indicating that the formation of the Chott el Jerid is unlikely to have been the barrier generating the vicariant evolution of the two lineages of A. australis, although it may have impeded their mixing following secondary contact. Both regional mtDNA lineages were found in A. australis hector and A. australisgarzonii, indicating that these two morphological forms are neither monophyletic nor geographically isolated and, therefore, should not be treated as species or subspecies. It is recommended that no subspecies of A. australis should be recognized in North Africa and toxicologists should cease the taxonomic error of referring to a species "Androctonus australis Hector". The morphological form "hector" has no proven association with an increased risk of scorpionism compared with "garzonii". However, it might be prudent to produce anti-venom in Tunisia by using both morphological forms of A. australis collected each side of the Chott el Jerid, because of the evidence for regional variation in toxins. The highest risk for scorpion stings occurs in the central region, where the new diagnostic markers should be used to discover any association between Androctonus species and scorpionism.

Mitochondrial 16S rDNA analysis of Tunisian androctonus species (Scorpions, Buthidae): phylogenetic approach

Tunisian Androctonus species, for long time discussed, were recognized on the basis of mitochondrial 16S rDNA sequences. Although the analysed nucleotide sequence is rather short (about 300 bp), the obtained phlogenetic trees revealed that A. amoreuxi and A. aeneas form two well-supported sister clades against A. australis haplotypes. Each specimen of the very rare species A. aeneas showed a specific haplotype, but together formed a well-defined clade. Some A. amoreuxi specimens highlighted unidirectional mitochondrial introgression from neighbouring A. australis population. Within A. australis, previously described, subspecies subdivision (A. a .hector and A. a. garzonii) was not supported.

[Probable origin of the Robertsonian phenomena in domestic mice in Tunisia]

The Robertsonian phenomenon in house mice (Mus musculus domesticus) from Tunisia consists in the presence of only one 22-chromosome Robertsonian race (22Rb) carrying the maximum number of fusions observed until now. The 22Rb populations exclusively occupy urban centers in the Eastern-Central region of Tunisia where standard population with 40-all acrocentric chromosomes (40Std) occur in surrounding neighborhoods and rural environments. In addition to the habitat partition, allozyme and mitochondrial DNA analyses showed that the 22Rb populations were genetically differentiated from the 40Std ones. This differentiation mostly stemmed from an important decrease in genetic variability in the 22Rb populations from the Sahel towns. The extent of morphological, ecological and genetical divergence observed between these chromosomal races in Tunisia is in agreement with the predictions of the chromosomal speciation model of White which advocates that karyotypic differentiation between taxa can lead to their reproductive isolation and independent evolution. Such a process is verified if the Rb process in Tunisia results from local differentiation which is supported by both the genetic and morphological data. However, the hypothesis of an origin by introduction of these mice from another region of Tunisia or from another country cannot be totally dismissed. In this study, an allozymic analysis of mice (22Rb and 40Std) from the geographically distant city of Kairouan was performed. Results showed that 22Rb and 40Std mice from Kairouan shared the same high degree of variability, and were not genetically differentiated. This contrasts with the results registered in the two chromosomal races in the Sahel towns. Such data argue in favor of a local differentiation of the Robertsonian process in Tunisia and suggest that the decrease in variability of the structural nuclear genes in the Sahel 22Rb populations can be related to an introduction from Kairouan into a Sahel locality resulting in a founder effect or followed by a severe bottleneck prior to its dispersion throughout the Sahel region.

Comparison of ribosomal ITS regions among Androctonus spp. sorpions (Scorpionida: Buthidae) from Tunisia

Three species of scorpions have been reported from Tunisia: Androctonus amoreuxi Audoin, A. aeneas Koch, and A. australis L. The latest has been divided in two subspecies: A. australis garzonii Goyffon & Lamy and A. australis hector Koch. Despite the public health importance of these animals, which cause several cases of poisoning each year, nothing is know about the genetic diversity of the group. To gain a better understanding of the group, we studied the variation of rDNA sequences of the ITS1, 5.8S, and ITS2 region of 14 representatives of the four taxa in Tunisia. The main result is the high polymorphism of the ITS regions. In some instances in both intra- and interspecific comparisons, it was difficult to unambiguously align the sequences. However, some representatives of different species were relatively similar, so that it appeared difficult to recognize the species on the basis of these sequences. A phylogenetic analysis was conducted that inquires the validity of the subspecies status of A. australis garzonii and A. australis hector. Moreover, the taxonomic status of A. aeneas is also questioned. Our studies highlighted the need of a revision of the taxonomy of the scorpions in Tunisia; however, the use of other genetic markers will be necessary to solve this question.

Microgeographical distribution of two chromosomal races of house mice in Tunisia: pattern and origin of habitat partitioning

Two chromosomal races of the house mouse occur in Tunisia, a standard morph (40St) found all over the country, and a derived morph (22Rb) occurring only in central Tunisia. In this region, habitat partitioning between the two morphs was investigated by a microgeographical analysis of their distribution, assessing habitat characteristics and demographic parameters. Results showed that the 22Rb mice always occurred in the oldest sections of towns (medinas), often extending to more recent surrounding neighbourhoods where the 40St morph was most abundant. The latter was never trapped within the medinas. The transition between the two morphs was located within cities in the more recent areas, the hybrid zone being estimated at less than 0.5 km in width by a clinal analysis of chromosomal data. Although differences between habitats exist, almost no demographic differences were found between populations of the two morphs when they occurred in the same or in different habitats. Two hypotheses are discussed to account for the origin of habitat partitioning. The first relies on competitive exclusion of the 40St mice from the medinas by the derived 22Rb mice; the second is based on stochastic processes related to historical evolution of Tunisian urban communities.

Juvenile idiopathic chronic calcifying pancreatitis: report of 10 cases from central Tunisia

A series of 10 cases of chronic calcifying pancreatitis from central Tunisia are reported. The mean age at presentation was 23 years and the male to female ratio was 1.5. The main clinical manifestations of the disease were abdominal pain (eight cases), weight loss (four cases), and diarrhea (three cases). Diabetes was recorded in four cases. The etiological investigations yielded negative results in all the patients. It is concluded that central Tunisia should be added to the regions where juvenile chronic calcifying pancreatitis of the "tropical type" may be observed.

[Exogastric cystic schwannoma. Observation of a case]

The authors report a case of giant gastric schwannoma with dominating extra-gastric development and a cystic component simulating a pancreatic pseudo-cyst on ultrasound and computed tomography examination, the diagnosis was made only at surgery that consisted in total gastrectomy. The rarity of these tumors, their diagnostic difficulties and the particularities of their surgical treatment are outlined.

[Complications of typhoid fever]

The authors report the complications noted in the course of 120 cases of typhoid fever. Intestinal hemorrhages and ileal perforations were the most frequent complications observed, respectively, among 12.5% and 3.3% of patients. Neuropsychiatric manifestations were also frequent: 6.7% of cases. Only one death was noted (0.8%). According to this high rate of complications, typhoid fever must be managed under hospital conditions.

Bigeminal arrhythmia associated with hyperparathyroid crisis

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[Clostridium perfringens septicemia]

We report 3 cases of Clostridium perfringens bacteremia with uterine gas gangrene. Clinical presentation included severe infectious syndrome, hemoglobinemia and hemoglobinuria, jaundice, uterine tenderness and hypertension. All 3 cases were first seen with installed renal failure. Diagnosis and modalities of therapy were reviewed. Clostridium perfringens bacteremia with uterine gas gangrene still occur in developing countries.

[Post-jejunoscopy bacteremia caused by Klebsiella pneumoniae]

We report a case of symptomatic Klebsiella pneumoniae bacteremia following a jejunoscopy. Occurrence of bacteremia in patients undergoing gastro-intestinal endoscopy is reviewed.