Description of Methicillin-Susceptible Staphylococcus aureus Clonal Complex 30 Related to the Pandemic Phage Type 80/81 Isolated from Patients in Three Tertiary Hospitals in Jos, North Central Nigeria.

OBJECTIVE: The prevalence of phage 80/81 Staphylococcus aureus strains, the pandemic strains that were dominant in the 1950s, had declined in the 1960s and 1970s. However, these strains have reemerged in some countries in recent years. This study investigated the antibacterial resistance, virulence, and the genetic backgrounds of CC30-MSSA isolates obtained from patients in three tertiary hospitals. MATERIALS AND METHODS: Twenty-two CC30-MSSA isolates cultured from different clinical samples were investigated using antibiotic sensitivity testing, spa typing, multilocus sequence typing, and DNA microarray analysis. RESULTS: All 22 isolates were susceptible to vancomycin (MIC ≤2 µg/mL), teicoplanin (MIC ≤2 µg/mL), and cefoxitin but were resistant to penicillin G (n = 22; 100.0%), tetracycline (n = 12; 54.5%), ciprofloxacin (n = 15; 68.2%), cadmium acetate (n = 22; 100%), mercuric chloride (n = 13; 59.1%), and ethidium bromide (n = 3; 13.6%). The isolates belonged to sequence type, ST30, and five spa types: t012 (n = 12; 54.5%), t019 (n = 5; 22.7%), t017 (n = 2; 9.1%), t037 (n = 2; 9.1%), and t318 (n = 1; 4.5%). All 22 isolates were positive for agrIII, cap8, clfA, clfB, icaA, icaC, icaD, cna, and staphylococcal enterotoxin gene clusters (seg, sei, sem, sen, seo, seu). Eight isolates carried lukS-PV and lukF-PV that code for Panton-Valentine leukocidin. CONCLUSION: The current CC30-MSSA isolates share phenotypic and genotypic characteristics with the pandemic phage 80/81 isolates that were common in the 1950s and 1960s. Continued surveillance is recommended to keep abreast of the changing epidemiology of S. aureus causing healthcare and community-associated infections.

Fusidic Acid Resistance Determinants in Methicillin-Resistant Staphylococcus aureus Isolated in Kuwait Hospitals.

OBJECTIVE: The aim of this study was to investigate the genetic determinants of fusidic acid (FA) resistance in MRSA isolated from patients in Kuwait hospitals. METHODS: The minimum inhibitory concentration (MIC) of FA was tested with E-test strips. Genetic determinants of FA were determined by PCR and DNA microarray. Staphylococcal protein A gene (spa) typing and DNA microarray analysis were used to study their genetic backgrounds. RESULTS: The FA MIC ranged from 2 mg/L to >256 mg/L. Of the 97 isolates, 79 (81.4%) harbored fusC, 14 isolates harbored fusA mutations (fusA), and 4 isolates harbored fusB. Isolates with fusA mutations expressed high FA MIC (MIC >256 mg/L), whereas those with fusC and fusB expressed low FA MIC (MIC 2-16 mg/L). The isolates belonged to 23 spa types and 12 clonal complexes (CCs). The major spa types were t688 (n = 25), t311 (n = 14), t860 (n = 8), and t127 (n = 6) which constituted 54.6% of the isolates. The 12 CCs were CC1, CC5, CC8, CC15, CC22, CC80, CC88, and CC97 with CC5 (45.6%) and CC97 (13.2%) as the dominant CCs. CONCLUSIONS: The MRSA isolates belonged to diverse genetic backgrounds with the majority carrying the fusC resistance determinants. The high prevalence of FA resistance belonging to diverse genetic backgrounds warrants a review of FA usage in the country to preserve its therapeutic benefits.

Antibiotic resistance and typing of the methicillin-resistant Staphylococcus aureus clones in Kuwait hospitals, 2016-2017.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) belong to diverse genetic backgrounds that differ in antibiotic resistance. Knowledge of the local clonal composition of MRSA strains is important for patients' management and for designing effective control and eradication methods. The aim of this study was to compare the antibiotic resistance patterns and genotypic characteristics of MRSA isolates obtained in public hospitals in Kuwait in 2016 and 2017 for changes in their resistance patterns and clonal composition. METHODS: A total of 4726 MRSA isolates obtained in 2016-2017 from clinical specimens in Kuwait public hospitals were characterized using antibiogram, SCCmec typing, spa typing and DNA microarray. RESULTS: The isolates expressed resistance to fusidic acid (52.9%), kanamycin (41.6%), gentamicin (32.5%) and erythromycin (36.2%). The prevalence of high-level mupirocin resistance decreased from 3.7% in 2016 to 2.4% in 2017, while the proportion of resistance to other antibiotics remained relatively stable. A total of 382 spa types were detected with eight spa types, t688 (N = 547), t304 (N = 428), t860 (N = 394), t127 (N = 306), t044 (N = 230), t311 (N = 243), t223 (N = 184) and t002 (N = 181) constituting 53.1% of the MRSA isolates in 2016-2017. Of the 3004 MRSA isolates obtained in 2016 (N = 1327) and 2017 (N = 1677) selected for DNA microarray analysis, 26 clonal complexes (CCs) were identified. Most of the isolates belonged to CC1 (N = 248), CC5 (N = 833), CC6 (N = 241), CC8 (N = 292), CC22 (N = 421), CC30 (N = 177), CC80 (N = 177) and CC97 (N = 171). The prevalence of CC5 isolates has significantly (p ≤ 0.05) increased from 294 isolates in 2016 to 539 isolates in 2017. Although CC22 increased from 196 isolates in 2016 to 225 isolates in 2017, CC1 increased from 112 isolates in 2016 to 136 isolates in 2017, CC6 increased from 103 isolates in 2016 to 138 isolates in 2017, these changes were not significant (p ≥ 0.05). CONCLUSION: These results revealed the diversity in the genetic backgrounds of MRSA isolates and the stable maintenance of the dominant MRSA clones in Kuwait hospitals in 2016 and 2017 suggesting an on-going transmission of these clones. Novel and creative infection prevention and control measures are required to curtail further transmission.

Genetic diversity of methicillin resistant Staphylococcus aureus strains isolated from burn patients in Iran: ST239-SCCmec III/t037 emerges as the major clone.

Methicillin-resistant Staphylococcus aureus (MRSA) as a major cause of infection in health care, hospital and community settings is a global health concern. The purpose of this study was to determine the antibiotic susceptibility pattern and distribution of circulating molecular types of MRSA in a burn hospital in Tehran, the capital of Iran. During a 10-month study period, 106 Staphylococcus aureus isolates were assessed. Isolates were subjected to susceptibility testing using the disk diffusion method and Polymerase Chain Reaction (PCR) for detection of mecA, fem and nuc genes. The presence of PVL and tst encoding genes were determined by PCR method. All the MRSA isolates were genotyped by multilocus sequence typing (MLST), spa typing, SCCmec typing and agr typing. The presence of mecA gene was confirmed in all the Staphylococcus aureus isolates. Antimicrobial susceptibility testing revealed a high resistance rate (90.6%) to ampicillin, tetracycline, and erythromycin. The rates of resistance to remaining antibiotics tested varied between 18.9% and 84.9%. The high- level of resistance to mupirocin was confirmed in 19.8% of MRSA strains isolated from burn patients. Multi-drug resistance was observed in 90.6% of isolates. Sixteen of the 106 MRSA isolates (15.1%) harbored PVL-encoding genes. The majority of our MRSA strains carried SCCmec III (71.7%). ST239-SCCmec III/t037 (34%) was the most common genotype followed by ST239-SCCmec III/t030 (24.5%), ST15-SCCmec IV/t084 (15.1%), ST22-SCCmec IV/t790 (13.2%), and ST239-SCCmec III/t631 (13.2%). Mupirocin resistant MRSA isolates belonged to ST15-SCCmec IV/t084 (40%), ST22-SCCmec IV/t790 (23.3%), ST239-SCCmec III/t631 (20%), and ST239-SCCmec III/t030 (16.7%) clones. The results showed that genetically diverse strains of MRSA are circulating in our burn hospitals with relatively high prevalence of ST239-SCCmec III/t037 clone. The findings support the need for regular surveillance of MRSA to determine the distribution of existing MRSA clones and to detect the emergence of new MRSA clones.

Antibiotic Resistance Trends in Methicillin-Resistant Staphylococcus aureus Isolated in Kuwait Hospitals: 2011-2015.

OBJECTIVE: The aim of this study was to determine antibiotic resistance trends and carriage of staphylococcal cassette chromosome mec (SCCmec) genetic elements in methicillin-resistant Staphylococcus aureus (MRSA) isolated in Kuwait hospitals to ascertain whether they were healthcare associated (HA-MRSA) or community associated (CA-MRSA). MATERIALS AND METHODS: In total, 6,922 MRSA isolates obtained from different clinical samples were tested for resistance to antibiotics, urease production, and carriage of SCCmec elements. RESULTS: All MRSA isolates were susceptible to linezolid, vancomycin, and teicoplanin. However, some isolates were resistant to kanamycin (2,979; 43%), ciprofloxacin (2,955; 42.7%), erythromycin and clindamycin (2,935; 42.4%), fusidic acid (2,858; 41.2%), gentamicin (2,665; 38.5%), tetracycline (2,652; 38.3%), and trimethoprim (2,324; 33.5%). Whereas the prevalence of resistance to most antibiotics showed annual variations, those resistant to chloramphenicol and rifampicin increased from 2.6 and 0.1% to 9.6 and 1.6%, respectively, and high-level mupirocin resistance declined from 9.3% in 2011 to 3.6% in 2015. In total, 3,244 (53.9%) of the isolates carried SCCmec IV followed by SCCmec III (1,737; 28.8%) and SCCmec V (890; 14.8%). SCCmec I (21; 0.3%) and II (79; 0.8%) occurred sporadically. A total of 3,651 (60.7%) of the isolates belonged to the CA-MRSA genotype and 2,290 isolates (38.1%) were identified as HA-MRSA. CONCLUSION: This study demonstrates changes in antibiotic resistance patterns of MRSA over time and reinforces the value of surveillance in detecting such changes for the benefit of infection control and patient management.

Community-acquired methicillin-resistant Staphylococcus aureus: the new face of an old foe?

The burden of infections caused by community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is increasing among different patient populations globally. As CA-MRSA has become established in healthcare facilities, the range of infections caused by them has also increased. Molecular characterization of CA-MRSA isolates obtained from different centers has revealed significant diversity in their genetic backgrounds. Although many CA-MRSA strains are still susceptible to non-ß-lactam antibiotics, multiresistance to non-ß-lactam agents has emerged in some clones, posing substantial problems for empirical and directed therapy of infections caused by these strains. Some CA-MRSA clones have acquired the capacity to spread locally and internationally. CA-MRSA belonging to ST80-MRSA-IV and ST30-MRSA-IV appear to be the dominant clones in the countries of the Gulf Cooperation Council (GCC). The emergence of pandemic CA-MRSA clones not only limits therapeutic options but also presents significant challenges for infection control. Continued monitoring of global epidemiology and emerging drug resistance data is critical for the effective management of these infections.

Emergence of methicillin-resistant Staphylococcus aureus in the Maternity Hospital, Kuwait.

OBJECTIVE: To establish the relatedness of methicillin-resistant Staphylococcus aureus (MRSA) isolates in the Maternity Hospital, Kuwait. MATERIALS AND METHODS: A total of 22 MRSA were isolated from 20 neonates and 1 mother in the Special Care Unit, Maternity Hospital, Kuwait. They were characterized using antibiogram, pulsed-field gel electrophoresis (PFGE), SCCmec typing, spa typing and multi locus sequence typing (MLST), and were screened for genes encoding Panton Valentine leukocidin (PVL) and capsular polysaccharide types 5 and 8. RESULTS: The isolates were resistant to cadmium acetate (n = 22 or 100%), trimethoprim (n = 13 or 59.1%), gentamicin (n = 7 or 31.8%), ciprofloxacin (n = 5 or 22.7%), erythromycin and clindamycin (n = 2 or 9.1%), tetracycline (n = 2 or 9.1%) and fusidic acid (n = 2 or 9.1%). Eight isolates contained genes for PVL while 15 and 6 carried genes for types 5 and 8 capsular polysaccharide, respectively. Molecular typing distinguished 12 clones. Ten of these clones consisted of 20 isolates belonging to ST60-SCCmec-IV-t3935 (5 isolates), ST6-SCCmec-IV-t6269 (4 isolates), ST194-SCCmec-IV-t6892 (3 isolates), ST1-SCCmec-V-t2962 (2 isolates) and 1 isolate each of ST77-SCCmec-IV-t339, ST935-SCCmec-V-t1084, ST1317-SCCmec-V-t1548, ST9-SCCmec-V-t5801, ST627-SCCmec-IV-t1340 and ST2148-SCCmec-IV-t2810. CONCLUSION: The study demonstrated the emergence of MRSA including novel ST60 and ST194 clones at the Maternity Hospital in Kuwait.

Genotypes and virulence genes in group B streptococcus isolated in the maternity hospital, Kuwait.

OBJECTIVE: To characterize group B streptococcus (GBS) isolates obtained from patients at the Maternity Hospital in Kuwait for their genotypes and carriage of virulence genes. MATERIALS AND METHODS: A total of 154 GBS isolates were obtained from July 1 to October 31, 2007, from vaginal swabs (n = 95), urine (n = 46), blood (n = 4) and miscellaneous sources (n = 9). Genotypes were obtained by pulsed-field gel electrophoresis (PFGE), following digestion with SmaI or EagI restriction enzymes. PCR was used to screen for the carriage of virulence genes including: surface protein of group B streptococcus (spb1), secreted fibrinogen-binding protein (fbsB), C5a peptidase (scpB), laminin-binding protein (lmb), α- (bca) and ß-subunits of the C protein (bac), resistance to protease immunity protein (rib), and phage-associated gene (pag); regulatory protein (dltR), and toxins CAMP factor (cfb), hyaluronidase (hylB) and superoxide dismutase (sodA). RESULTS: PFGE defined 14 genotypes differentiating isolates with the same serotypes into different genetic backgrounds. All isolates contained genes for virulence factors. However, cfb (99.4%), scpB (88.3%), lmb (88.3%), bca (57.8%), sodA (55.8%) and dltR (53.9%) were the common virulence genes. In total, 144 (90.3%) of the isolates contained 3 or more virulence genes. However, while cfb, lmb and scpB occurred in all genotypes, others occurred in some but not in all genotypes. CONCLUSIONS: GBS isolates obtained at the Maternity Hospital, Kuwait, belonged to diverse genetic backgrounds with the majority carrying multiple virulence genes.

Methicillin-Resistant Staphylococcus aureus (MRSA) in a Tertiary Care Hospital in Kuwait: A Molecular and Genetic Analysis.

Methicillin-resistant Staphylococcus aureus (MRSA) is a major pathogen that causes serious infections in healthcare facilities and in communities. The purpose of this study was to investigate MRSA isolates obtained in a tertiary hospital in Kuwait to assess their antibiotic susceptibility profile and clonal composition. Sixty MRSA isolates collected in 2020 were tested through antibiotic susceptibility testing, spa typing, and DNA microarray analysis. All isolates were found to be susceptible to vancomycin (MIC: ≤3 µg/mL), teicoplanin (MIC: ≤3 µg/mL), rifampicin, and mupirocin, but were resistant to fusidic acid (n = 43, 72%), trimethoprim (n = 27, 45%), ciprofloxacin (n = 31, 51.7%), gentamicin (n = 14; 23.3%), kanamycin (n = 20; 33.3%), chloramphenicol (n = 7; 11.7%), tetracycline (n = 17; 28.3%), erythromycin (n = 19; 31.6%), inducible clindamycin (n = 13; 21.7%), and constitutive clindamycin (n = 2; 3.3%). The isolates belonged to 30 spa types and 13 clonal complexes (CCs). The dominant spa types were t304, t442, t311, t688, and t1234, collectively constituting 28.3% of the isolates. The dominant CCs were CC5 and CC6, which together constituted 46.7% of the isolates. This study provides updated research on antibiotic resistance and changes in the clonal composition of MRSA in a Kuwait hospital, including the disappearance of the ST239-MRSA-III clone that was previously the dominant clone in this hospital.

Effects of varied substituents on the antibacterial activity of triazolylmethyl oxazolidinones.

A number of 1,2,3-triazolylmethyl piperazino oxazolidinone derivatives with optionally varied substituents at the 4N-piperazine position were synthesized and their antibacterial activity evaluated against a panel of susceptible and resistant Gram-positive and selected Gram-negative bacteria. Substitution with 5-membered heteroaroyl and dinitrobenzoyl moieties potentiated activity against staphylococci and enterococci strains. Furthermore, the compounds having dinitrobenzoyl 7n, 7o, and 5-nitrofuroyl 7t substitutions were four- to eightfold more potent than linezolid against M. catarrhalis. However, substitution of guanidino and other water-solubilizing functionalities at the 4N-piperazine position resulted in compounds that are devoid of antibacterial activity.

Diversity of clonal complex 22 methicillin-resistant Staphylococcus aureus isolates in Kuwait hospitals.

CC22-MRSA is a major MRSA lineage that is widely reported globally. To characterize CC22-MRSA for trends in antibiotic resistance and emergence of variants, a total of 636 CC22 isolates identified by DNA microarray in 2016 (n = 195), 2017 (n = 227) and 2018 (n = 214) were investigated further using staphylococcal protein A (spa) typing and multilocus sequence typing. The isolates belonged to 109 spa types dominated by t223 (n = 160), t032 (n = 60), t852 (n = 59), t005 (n = 56) and t309 (n = 30) and 10 sequence types (STs) dominated by ST22 (85.5%). Genotypes CC22-MRSA-IV [tst1+]; CC22-MRSA-IV UK-EMRSA-15/Barnim EMRSA variants, CC22-MRSA-IV [PVL+], CC22-MRSA-IV [tst1+/PVL+] and CC22-MRSA-IV + V constituted >50% of the isolates. An increase from 2016 to 2018 were shown in isolates belonging to spa types t223 (43 to 62), t032 (18 to 27) and t309 (10 to 15) and genotypes CC22-MRSA-IV [tst1+] (89 to 102), CC22-MRSA-IV + V (12 to 30) and CC22-MRSA-IV [tst1+/PVL+] (12 to 22). Ninety-nine CC22-MRSA isolates were multi-resistant to three or more antibiotic classes with 76.7% of them belonging to CC22-MRSA-IV [PVL+] and CC22-MRSA-IV [tst1+/PVL+]. The study revealed an ongoing domination of the CC22-MRSA-[tst1+] genotype and the emergence of new clones bearing SCCmec IV + V and multiply resistant variants.

Frequency of virulence-associated genes in Enterococccus faecalis isolated in Kuwait hospitals.

OBJECTIVE: The objective of this study was to investigate the carriage of 6 virulence-associated genes in Enterococcus faecalis isolates obtained from patients in 8 hospitals in Kuwait. MATERIALS AND METHODS: In total, 466 E. faecalis isolates were obtained from 313 urine samples, 68 wound swabs, 36 blood samples, 25 rectal swabs, 12 high vaginal swabs and 12 miscellaneous sources. Genes for gelatinase(gelE),aggregation substance (aggA), hemolysin activation factor (cylA), enhanced expression of pheromone (eep), enterococcal surface protein (esp), and E. faecalis endocarditis antigen A (efaA) were detected in PCR assays. RESULTS: Of 466 isolates, 423 (90.8%) were positive for 1 and up to 5 genes. However, none of the genes was detected in all of the isolates. The prevalence of the individual genes was eep: 31.9%; esp: 31.5%; gelE: 28.5%; efaA: 27.9%; aggA: 23.4%, and cylA: 18.5%. Of the 423 positive isolates, 148 (34.9%) were positive for 2 genes and 52 (12.3%), 15 (3.5%) and 5 (0.9%) isolates were positive for 3, 4 and 5 virulence genes, respectively. The efaA and esp combination was detected in isolates from all clinical sources. CONCLUSION: The study showed a high prevalence of virulence genes in E. faecalis isolated in Kuwait hospitals. The absence of a dominant gene in all of the isolates suggests that infections by E. faecalis may require the involvement of multiple virulence factors.

Trafficking of methicillin-resistant staphylococci and co-colonization with vancomycin-resistant enterococci.

OBJECTIVES: To determine the trafficking of methicillin-resistant staphylococci between the hospital and community as well as the occurrence of co-colonization with vancomycin-resistant enterococci (VRE). SUBJECTS AND METHODS: From November 2005 to April 2006, methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative Staphylococcus (MRCoNS)-positive patients at the Salmaniya Medical Complex, Bahrain were assessed for VRE co-colonization. Characterization of vancomycin resistance genotype by PCR was carried out. Close family contacts were screened for MRSA and pulsed-field gel electrophoresis (PFGE) analysis of MRSA isolates from patient-family member pairs was conducted. RESULTS: One hundred and eighty-two patients (93 MRSA; 89 MRCoNS) and 356 family members were enrolled. Seven MRSA and 41 MRCoNS strains were isolated from the family members. PFGE analysis revealed the presence of variants of a single MRSA clone among patients and their relatives. A total of 112 patients (62 MRSA; 50 MRCoNS) provided stool for VRE screening. Of these 13 stool specimens (11.6%) were VRE-positive. All the VRE isolates were from MRSA-positive patients, thus positivity rate among MRSA patients was 20.9% (n/N = 13/62). These were predominantly Enterococcus gallinarum with vanC1 genotype and one strain was Enterococcus faecium (vanB genotype). Two E. gallinarum isolates harbored an additional vanB gene. The majority of VRE isolates were from patients in medical and surgical units (n/N = 10/13; 77%). Male gender, prolonged hospitalization and presence of co-morbidities were significantly associated with MRSA/VRE co-colonization (p < 0.05). CONCLUSION: MRSA/VRE co-colonization with MRSA trafficking between the hospital and community environment is a public health concern occurring in our setting.

Resurgence of Chloramphenicol Resistance in Methicillin-Resistant Staphylococcus aureus Due to the Acquisition of a Variant Florfenicol Exporter (fexAv)-Mediated Chloramphenicol Resistance in Kuwait Hospitals.

Following a surge in the prevalence of chloramphenicol-resistant methicillin-resistant Staphylococcus aureus (MRSA) in Kuwait hospitals, this study investigated the genotypes and antibiotic resistance of the chloramphenicol-resistant isolates to ascertain whether they represented new or a resurgence of sporadic endemic clones. Fifty-four chloramphenicol-resistant MRSA isolates obtained in 2014-2015 were investigated. Antibiotic resistance was tested by disk diffusion and MIC determination. Molecular typing was performed using spa typing, multilocus sequence typing, and DNA microarray. Curing and transfer experiments were used to determine the genetic location of resistance determinants. All 54 isolates were resistant to chloramphenicol (MIC: 32-56 mg/L) but susceptible to florfenicol. Two chloramphenicol-resistance determinants, florfenicol exporter (fexA) and chloramphenicol acetyl transferase (cat), were detected. The fexA-positive isolates belonged to CC5-ST627-VI-t688/t450/t954 (n = 45), CC5-ST5-V-t688 (n = 6), whereas the cat-positives isolates were CC8-ST239-III-t037/t860 (n = 3). While cat was carried on 3.5-4.4 kb plasmids, the location of fexA could not be established. DNA sequencing of fexA revealed 100% sequence similarity to a previously reported fexA variant that confers chloramphenicol but not florfenicol resistance. The resurgence of chloramphenicol resistance was due to the introduction and spread of closely related fexA-positive CC5-ST5-V and CC5-ST627-VI clones.

The Dissemination and Molecular Characterization of Clonal Complex 361 (CC361) Methicillin-Resistant Staphylococcus aureus (MRSA) in Kuwait Hospitals.

Methicillin-resistant Staphylococcus aureus (MRSA) belonging to clonal complex 361 (CC361-MRSA) is rare among patients' populations globally. However, CC361-MRSA has been isolated with an increasing trend among patients in Kuwait hospitals since 2010. This study investigated the molecular characteristics of CC361-MRSA isolated from patients in Kuwait hospitals in 2016-2018 to understand their genetic relatedness and virulence determinants. Of 5,223 MRSA isolates investigated by DNA microarray, 182 (3.4%) isolates obtained in 2016 (N = 55), 2017 (N = 56), and 2018 (N = 71) were identified as CC361-MRSA. The CC361-MRSA isolates were analyzed further using antibiogram, spa typing and multi locus sequence typing (MLST). Most of the isolates were resistant to fusidic acid (64.8%), kanamycin (43.4%), erythromycin (36.3%), and clindamycin (14.3%) encoded by fusC, aphA3, and erm(B)/erm(C) respectively. Nine isolates (4.9%) were resistant to linezolid mediated by cfr. The isolates belonged to 22 spa types with t3841 (N = 113), t315 (N = 16), t1309 (N = 14), and t3175 (N = 5) constituting 81.3% of the spa types, four genotypes (strain types), CC361-MRSA-[V/VT + fus] (N = 112), CC361-MRSA-IV, WA MRSA-29 (N = 36), CC361-MRSA-V, WA MRSA-70/110 (N = 33) and CC361-MRSA-[V + fus] variant (N = 1). MLST conducted on 69 representative isolates yielded two sequence types: ST361 (11/69) and ST672 (58/69). All CC361-MRSA isolates were positive for cap8, agr1, and the enterotoxin egc gene cluster (seg, sei, selm, seln, selo, and selu). The tst1 was detected in 19 isolates. The immune evasion cluster (IEC) genes type B (scn, chp, and sak) and type E (scn and sak) were detected in 20 and 152 isolates, respectively. The CC361-MRSA circulating in Kuwait hospitals consisted of two closely related sequence types, ST361 and ST672 with ST672-MRSA [V/VT + fus] as the dominant genotype. The dissemination of these newly emerged clones and the emergence of linezolid resistance limits therapeutic options, as well as present significant challenges for the control of MRSA infections in Kuwait hospitals.

Characterisation of S. aureus/MRSA CC1153 and review of mobile genetic elements carrying the fusidic acid resistance gene fusC.

While many data on molecular epidemiology of MRSA are available for North America, Western Europe and Australia, much less is known on the distribution of MRSA clones elsewhere. Here, we describe a poorly known lineage from the Middle East, CC1153, to which several strains from humans and livestock belong. Isolates were characterised using DNA microarrays and one isolate from the United Arab Emirates was sequenced using Nanopore technology. CC1153 carries agr II and capsule type 5 genes. Enterotoxin genes are rarely present, but PVL is common. Associated spa types include t504, t903 and t13507. PVL-positive CC1153-MSSA were found in Egyptian cattle suffering from mastitis. It was also identified among humans with skin and soft tissue infections in Saudi Arabia, France and Germany. CC1153-MRSA were mainly observed in Arabian Gulf countries. Some isolates presented with a previously unknown SCCmec/SCCfus chimeric element in which a mec B complex was found together with the fusidic acid resistance gene fusC and accompanying genes including ccrA/B-1 recombinase genes. Other isolates carried SCCmec V elements that usually also included fusC. Distribution and emergence of CC1153-MRSA show the necessity of molecular characterization of MRSA that are resistant to fusidic acid. These strains pose a public health threat as they combine resistance to beta-lactams used in hospitals as well as to fusidic acid used in the community. Because of the high prevalence of fusC-positive MRSA in the Middle East, sequences and descriptions of SCC elements harbouring fusC and/or mecA are reviewed. When comparing fusC and its surrounding regions from the CC1153 strain to available published sequences, it became obvious that there are four fusC alleles and five distinct types of fusC gene complexes reminiscent to the mec complexes in SCCmec elements. Likewise, they are associated with different sets of ccrA/B recombinase genes and additional payload that might include entire mec complexes or SCCmec elements.

The dissemination of ST80-SCCmec-IV community-associated methicillin resistant Staphylococcus aureus clone in Kuwait hospitals.

BACKGROUND: Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is a global healthcare problem. The purpose of this study was to characterize CA-MRSA clones and their distribution in Kuwait hospitals. METHODS: In total, 135 CA-MRSA isolates, carrying the SCCmec IV or V genetic elements, isolated in eight hospitals were characterized using antibiogram, pulsed-field gel electrophoresis, multilocus sequence typing, and carriage of genes for Panton-Valentine Leukocidin (PVL), capsular polysaccharides types (cap) 5 and 8, accessory genes regulators (agr), Staphylococcal enterotoxins (SE) and toxic shock syndrome toxin 1 (tst). RESULTS: They were susceptible to vancomycin, teicoplanin and linezolid but resistant to kanamycin (62%), fusidic acid (42.2%), tetracycline (39.3%), erythromycin and clindamycin (21.5%), gentamicin (5.9%), streptomycin (6.7%), trimethoprim (5.9%), mupirocin (6.6%) and cadmium acetate (82.2%). They consisted of 10 pulsotypes with the majority belonging to PFGE type I (51.1%), type II (22.2%), type IV (13.3%) and type III (3.7%). They belonged to 10 sequence types (ST) comprising ST80 (51.1%), ST30 (22.2%), ST5 (14.1%), ST1 (4.45), ST6 (3.7%), ST88 (1.5%), ST834 (1.5%), ST8 (0.7%), ST46 (0.7%) and ST950 (0.7%). Genes for PVL, cap 8, cap 5 and agr III, agr I and agr II were detected in 61.5%, 77.3%, 20.7% and 62.2%, 17% and 8.1% of the isolates respectively. Nine (6.7%) isolates contained tst while 103 isolates were positive for SE genes with sei (63.0%), seg (41.5%) and sed (29.6%) as the common SE genes. CONCLUSIONS: ST80-SCCmecIV was the most common CA-MRSA clone in Kuwait hospitals presenting new challenges for infection control.

Antimicrobial resistance and virulence determinants in coagulase-negative staphylococci isolated mainly from preterm neonates.

Coagulase-negative staphylococci (CoNS) are the most common isolates from blood culture in neonates resulting in high mortality and morbidity. This study investigated CoNS obtained from blood cultures of neonates for antibiotic resistance and virulence factors, and possible association with inflammatory response (C-reactive protein). A total of 93 CoNS isolates were collected from 76 blood cultures of neonates at the Maternity hospital in Kuwait in a six-month period and investigated for susceptibility to antibiotics, carriage of staphylococcal cassette chromosome mec (SCCmec), and virulence-associated genes. The 93 CoNS isolates consisted of S. epidermidis (76; 81.7%), S. capitis (12; 12.9%), S. hominis (2; 2.1%), S. warneri (2; 2.1%) and S. haemolyticus (1; 1.0%). Eighty-six (92.4%) of the isolates were resistant to cefoxitin (MR-CoNS) while 49 (52.7%) expressed multi-antibiotic resistance. The methicillin-resistant isolates (MR-CoNS) carried SCCmec III, SCCmec IVa and four combinations of SCCmec types including SCCmec types I+IVa (one S. warneri and 25 S. epidermidis isolates), types I+III (one S. epidermidis isolate), types III+IVa (six S. epidermidis isolates) and types I+III+IVa (one S. epidermidis isolate). The most common virulence-related genes were icaC, seb, arc detected in 69.7%, 60.5%, 40.8% of the isolates respectively. Two isolates were positive for tst1. No association between C-reactive protein and antibiotic resistance or virulence factors was established. This study revealed that S. epidermidis carrying different SCCmec genetic elements, was the dominant CoNS species isolated from neonatal blood cultures with 90.3% and 36.6% of the isolates positive for genes for biofilm and ACME production respectively.

Emergence of Methicillin-Resistant Staphylococcus aureus Belonging to Clonal Complex 15 (CC15-MRSA) in Kuwait Hospitals.

PURPOSE: Methicillin-resistant S. aureus (MRSA) belonging to clonal complex 15 (CC15-MRSA) is rare among clinical isolates with few reports from retail camel meat and human patients. This study investigated the genetic relatedness of CC15-MRSA isolated for the first time from patients in Kuwait hospitals. METHODS: Antibiotic susceptibility was tested by the disk diffusion method. Minimum inhibitory concentration was determined using Etest strips. Molecular typing was performed using spa tying, multilocus sequence tying and DNA microarray. RESULTS: Of 1327 MRSA isolates, 42 (3.1%) were identified as CC15-MRSA. The 42 isolates belonged to sequence type ST1535-harbored SCCmec type V and spa types t084 (36 isolates), t346 (3 isolates) and one of t114, t228 and t7583. All 42 isolates were resistant to gentamicin, kanamycin, fusidic acid and cadmium acetate; 38 isolates were resistant to tetracycline. The isolates harbored aacA-aphD and fusC that codes for gentamicin and fusidic acid resistance, respectively. Tet(K) was present in the tetracycline-resistant isolates. In addition, the 42 isolates carried inu(A) (lincosamide nucleotidyltransferase) that confers resistance to lincomycin and clindamycin although phenotypically susceptible to these antibiotics. The isolates belonged to accessory gene regulator type II and capsular polysaccharide group 8 but lacked genes for Staphylococcus enterotoxins, toxic shock syndrome toxin, collagen-binding adhesins and Panton-Valentine leukocidin. CONCLUSION: This study revealed the emergence and transmission of a previously rare MRSA clone among human patients in Kuwait hospitals and highlights the increasing infiltration of rare MRSA into the human population.

Ciprofloxacin-resistant Salmonella enterica serovar typhi from Kuwait with novel mutations in gyrA and parC genes.

Blood isolates of Salmonella enterica serovar Typhi from two recently returned Bangladeshi patients in Kuwait were ciprofloxacin resistant, with ciprofloxacin MICs of 12 mg/liter for both isolates. Both isolates had three novel gyrA mutations (55-Leu-->Trp, 87-Asp-->Ala, and 106-Gln-->Arg) and three novel parC mutations (84-Glu-->Lys, 106-Trp-->Gly, and 128-Tyr-->Asp).