Widespread of the Vienna/Hungarian/Brazilian CC8-ST239-SCCmec III MRSA clone in patients hospitalized in the Tunisian Burn and Traumatology Center.

The emergence and spread of methicillin-resistant Staphylococcus aureus (MRSA) in hospitals is a major global public health concern. The current study sought to characterize 25 MRSA clinical isolates collected in a Tunisian hospital from December 2015 to September 2016, with the genetic lineages, virulence factors, and antibiotic resistance mechanisms determined for these isolates. Three spa-types were detected: t037 (23 isolates), t932, and t2235 (one isolate each). Isolates were ascribed to agr I (n = 20), agr II (n = 1), with four nontypeable isolates. Depending on sequence type (ST), the 25 MRSA isolates were assigned to two clonal complexes (CC8 and CC5), with a predominance of the lineage ST239-CC8 (n = 24; 96%). All isolates belonging to CC8 had the SCCmec type III, while the unique CC5 isolate had SCCmec type IV. Antimicrobial susceptibility testing revealed high levels of resistance to aminoglycosides, tetracycline, ciprofloxacin and rifampicin for the majority of isolates belonging to the ST239-CC8 lineage. The ST149-CC5 isolate was susceptible to non-ß-lactam antibiotics. One isolate harbored the tsst-1 gene (4%); however, lukS/LukF-PV, eta and etb genes were not detected. The MDR ST239-CC8 clone would seem to be widespread in this hospital. Therefore, a rigorous hygienic control system is urgently required.

Multidrug Resistance and the Predominance of blaCTX-M in Extended Spectrum Beta-Lactamase-Producing Enterobacteriaceae of Animal and Water Origin.

The aim of this work was the genetic characterization of cefotaxime-resistant enterobacteria from animals (53 samples), the surface water of rivers (17 samples), and wastewater treatment plants (43 samples) in Tunisia. A total of 48 (42.4%) cefotaxime-resistant isolates were recovered. An extended spectrum beta-lactamase (ESBL) phenotype with a positive double-disk synergy test (DDST) was exhibited by 34 (70.8%) and 14 (29.1%) isolates from water and animal origins, respectively. Isolates from water were identified as: Escherichia coli (n = 17), Hafnia spp. (n = 13), Citrobacter spp. (n = 1), Enterobacter cloacae (n = 1), Klebsiella pneumoniae (n = 1), and K. oxytoca (n = 1). Animal isolates were identified as: E. coli (n = 11), E. cloacae (n = 1), Hafnia spp. (n = 1), and K. pneumoniae (n = 1). PCR investigation of blaCTX-M, blaTEM, and blaSHV genes showed that amongst the 48 isolates with a positive DDST, 41 (87.5%) carried the blaCTX-M gene, 1 isolate harbored the blaSHV gene, and 1 isolate coharbored blaCTX-M with blaSHV genes. The class 1 and 2 integrons were detected in 27 (56.2%) and 1 (2%) isolates, respectively. Our study showed a significant occurrence of ESBL-producing enterobacteria in animals and aquatic environments with a predominance of blaCTX-M genes.

Staphylococcus aureus isolated from wastewater treatment plants in Tunisia: occurrence of human and animal associated lineages.

The objective was to characterize Staphylococcus aureus isolated from two wastewater treatment plants (WWTPs) located in Tunis City (Tunisia), during the period 2014-2015. Genetic lineages, antibiotic resistance mechanisms and virulence factors were determined for the recovered isolates. S. aureus isolates were recovered from 12 of the 62 wastewater samples tested (19.35%), and one isolate/sample was characterized, all of them being methicillin-susceptible (MSSA). Six spa types (t587, t674, t224, t127, t701 and t1534) were found among the 12 isolates, and the spa-t587, associated with the new sequence type ST3245, was the most predominant one (7 isolates). The remaining isolates were assigned to five clonal complexes (CC5, CC97, CC1, CC6 and CC522) according to the sequence-type determined and/or the spa-type detected. S. aureus isolates were ascribed to agrI (n = 3), agrII (n = 7) and agrIII (n = 1); however, one isolate was non-typeable. S. aureus showed resistance to (number of isolates): penicillin (12), erythromycin (7), tetracycline (one) and clindamycin (one). Among the virulence factors investigated, only one isolate harboured the tst gene, encoding the TSST-1 (toxic shock syndrome toxin 1). Despite the low number of studied isolates, the present study reports the occurrence of both human- and animal-associated S. aureus clonal complexes in WWTPs in Tunisia.

Genetic characterization of Staphylococcus aureus isolated from nasal samples of healthy ewes in Tunisia. High prevalence of CC130 and CC522 lineages.

Staphylococcus aureus is a versatile bacterium, which can infect or colonize a variety of host species. The objective of this study was to characterize S. aureus isolates recovered from nasal swabs of 167 healthy ewes sampled from 12 farms in different areas of Tunisia during the period of 2014-2015. Genetic lineages, virulence factors and antibiotic resistance mechanisms were determined for recovered isolates. S. aureus was detected in 45 out of 167 tested samples (26.9%). All isolates were methicillin-susceptible (MSSA) and the majority of them were susceptible to tested antibiotics with few exceptions (% of resistance): penicillin (8.8), ciprofloxacin (4.4), and tobramycin or tetracycline (2.2, each). Twelve different spa types were detected (t15098, t15099, t1773, t3576, t1534, t5428, t3750, t5970 t254, t2883, t127 and t933), two of them were new (t15098 and t15099). S. aureus isolates were ascribed to agrI (n=23), agrII (n=1) and agrIII (n=20), and one was non-typeable. According to the sequence-type (ST) determined and/or the spa-type detected, the 45S. aureus isolates were assigned to six clonal complexes, with CC522 (44.4%) and CC130 (37.7%) being the most common lineages. Twenty-one (46.6%) and two (4.2%) isolates harbored the tst and eta genes encoding TSST-1 and ETA, respectively. In conclusion, nares of healthy ewes could be a reservoir of MSSA CC522 and CC130, lineages associated with TSST-1 and ETA that might represent a risk to human health.