Methicillin-resistant Staphylococcus aureus ST80-IV clone in children from Jordan.

Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of infections that are becoming increasingly difficult to combat because of emerging resistance. In this study, 103 S. aureus, 41 MRSA and 62 methicillin-sensitive Staphylococcus aureus isolates, were collected from children in Jordan. Genotyping based on spa and multilocus sequence typing (MLST) revealed 48 different spa types and identified distinct allelic profiles or STs, with the majority belonging to ST80. Pulsed-field gel electrophoresis (PFGE) of 15 different spa types revealed 8 different PFGE types, while SCCmec showed the predominance (53%) of subtype IV. Clustering SCCmec along with MLST revealed that ST80-MRSA-IV was the dominant type. Results obtained suggest that a significant amount of clonal spread is occurring in Jordan. The mechanism of spread of the ST80-IV clone is not known, and control measures are needed to reduce further spread of this or of other clones among children in Jordan.

emm typing, antibiotic resistance and PFGE analysis of Streptococcus pyogenes in Lebanon.

One hundred and three Streptococcus pyogenes isolates recovered mainly from streptococcal throat infections in Lebanon were characterized by emm and PFGE typing. Thirty-three emm types and subtypes were detected among the isolates. PFGE was more discriminatory as a typing method. The prevalent emm types were emm1 (12.6 %), emm22 (8.7 %), emm28 (7.7 %), emm88 (7.7 %) and emm4 (6.8 %) and all isolates were susceptible to vancomycin and penicillin G. Ten per cent of the isolates were resistant to erythromycin and 3 % were resistant to erythromycin and clindamycin, showing the macrolide-lincosamide-streptogramin B phenotype. The emm sequences and PFGE pattern database that were generated in this study will serve as a basis for information for long-term evolutionary and epidemiological studies of local S. pyogenes recovered not only in Lebanon, but also in neighbouring countries.

Toxins and Antibiotic Resistance in Staphylococcus aureus Isolated from a Major Hospital in Lebanon.

Molecular characterization of Staphylococcus aureus is of both clinical and infection control importance. Virulence determinants using PCR and multiple drug resistance profiles were studied in 130 S. aureus isolates. PCR-RFLP analysis of the 16S-23S DNA spacer region was done to investigate the level of 16S-23S ITS (internal transcribed spacer) polymorphism. Methicillin-resistant S. aureus (MRSA), which represented 72% of the studied isolates, showed multiple drug resistance with 18% being resistant to 10-18 of the drugs used compared to a maximum resistance to 9 antibiotics with the methicillin sensitive S. aureus (MSSA) isolates. Exfoliative toxin A (ETA) was more prevalent than B (ETB) with virulent determinants being additionally detected in multiple drug-resistant isolates. 16S-23S ITS PCR-RFLP combined with sequencing of the primary product was successful in generating molecular fingerprints of S. aureus and could be used for preliminary typing. This is the first study to demonstrate the incidence of virulent genes, ACME, and genetic diversity of S. aureus isolates in Lebanon. The data presented here epitomize a starting point defining the major genetic populations of both MRSA and MSSA in Lebanon and provide a basis for clinical epidemiological studies.

Geographical structure of the Y-chromosomal genetic landscape of the Levant: a coastal-inland contrast.

We have examined the male-specific phylogeography of the Levant and its surroundings by analyzing Y-chromosomal haplogroup distributions using 5874 samples (885 new) from 23 countries. The diversity within some of these haplogroups was also examined. The Levantine populations showed clustering in SNP and STR analyses when considered against a broad Middle-East and North African background. However, we also found a coastal-inland, east-west pattern of diversity and frequency distribution in several haplogroups within the small region of the Levant. Since estimates of effective population size are similar in the two regions, this strong pattern is likely to have arisen mainly from differential migrations, with different lineages introduced from the east and west.

Use of the 16S-23S ribosomal genes spacer region for the molecular typing of sphingomonads.

The ability of sphingomonads in drinking water to cause community- and hospital-acquired opportunistic infections has raised the need to establish reproducible identification assays. In this study, a total of 129 isolates recovered from drinking water with yellow- to orange-pigmented colonies were distributed among 10 biotypes on the basis of colony morphology. Polymorphisms, based on the amplification and restriction digestion of the intergenic transcribed spacer (ITS) region within the 10 assigned biotypes and 18 ATCC reference strains, were used to investigate the ability of this approach to differentiate closely related sphingomonads. ITS size, which ranged between 400 and 1100 bp, did not vary enough among the different genera. However, 16 distinct banding patterns within the ATCC reference strains and 9 within the 10 biotypes were obtained through ITS restriction digestion, and the majority of the tested biotypes produced patterns similar to those generated by the ATCC strains. To our knowledge, this study is not only the first comprehensive record of the size of the ITS region in sphingomonads, it is also the first study that describes the use of ITS restriction digestion to subtype those isolates.

Phylogenetic assessment of heterotrophic bacteria from a water distribution system using 16S rDNA sequencing.

Determination of a heterotrophic plate count (HPC) for drinking-water samples alone is not enough to assess possible health hazards associated with sudden changes in the bacterial count. Speciation is very crucial to determine whether the population includes pathogens and (or) opportunistic pathogens. Most of the isolates recovered from drinking water samples could not be allocated to a specific phylogenetic branch based on the use of conventional diagnostic methods. The present study had to use phylogenetic analysis, which was simplified by determining and using the first 500-bp sequence of the 16S rDNA, to successfully identify the type and species of bacteria found in the samples. Gram-positive bacteria alpha-, beta-, and gamma-Proteobacteria were found to be the major groups representing the heterotrophic bacteria in drinking water. The study also revealed that the presence of sphingomonads in drinking water supplies may be much more common than has been reported so far and thus further studies are merited. The intermittent mode of supply, mainly characterized by water stagnation and flow interruption associated possibly with biofilm detachment, raised the possibility that the studied bacterial populations in such systems represented organisms coming from 2 different niches, the biofilm and the water column.

Phenotypic and genotypic identification of Aeromonas spp. isolated from a chlorinated intermittent water distribution system in Lebanon.

Aeromonas spp. were detected in samples collected from both untreated groundwater and treated drinking water in Lebanon. Aeromonas spp. levels ranged between 2 and 1,100 colonies per 100 ml in the intake underground well and between 3 and 43 colonies per 100 ml in samples from the distribution system. Samples positive for Aeromonas spp. from the network had a free chlorine level ranging between 0 and 0.4 mg l(-1). Multiple antibiotic-resistance was common among the isolated aeromonads; all were resistant to amoxycillin while 92% showed resistance to cephalexin. Haemolysis on blood agar was detected in 52% of the isolates recovered from the distribution network and 81% of isolates from the untreated underground source. The Biolog microbial identification system assigned identities to all of the isolated presumptive aeromonads (at least at the genus level), which was not the case with the API 20NE strips. Differences at the species level were observed when results from the Biolog system were compared with identification based on the MicroSeq 500 16S rDNA sequence analysis. The presence of Aeromonas spp. in drinking water can be an important threat to public health, thus greater awareness of Aeromonas strains as potential enteropathogens is warranted.