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.

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.

Livestock-Associated Methicillin-Resistant Staphylococcus aureus in Patients Admitted to Kuwait Hospitals in 2016-2017.

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) has been reported to colonize and cause infections in animals as well as in humans. LA-MRSA isolates have only recently been identified in patients admitted to Kuwait hospitals. This study was conducted to characterize LA-MRSA isolates obtained from patients admitted to Kuwait hospitals. A total of 202 (7.1%) of 2,823 MRSA isolates obtained from clinical samples in 2016 and 2017 in 11 public Kuwait hospitals were assigned to lineages previously known to be associated with livestock. They were characterized using antibiogram, spa typing, and DNA microarray for the assignment of clonal complexes (CCs) and detection of antibiotic resistance and virulence determinants. Identification as putative LA-MRSA clones was based on the molecular definition inferred from DNA microarray. The LA-MRSA isolates consisted of CC96 (N = 31), CC97 (N = 169), and CC398 (N = 2). Isolates belonging to CC96 and CC398 were resistant to erythromycin and clindamycin mediated by erm(A) and erm(C). CC97 isolates were multiresistant to gentamicin, kanamycin, erythromycin, clindamycin, tetracycline, chloramphenicol, fusidic acid, trimethoprim, and ciprofloxacin and harbored aacA-aphD, erm(A), erm(C), msr(A), tet(K), cat, fusC, and dfrS1. In total, 35 spa types were identified among the isolates. CC398 isolates consisted of t899 and t034. Ten spa types were identified among CC96 with t11822 (N = 13) as the most prevalent. CC97 consisted of 26 spa types with most belonging to t267 (N = 73) followed by t359 (N = 39). CC398 was composed of CC398-MRSA-IV and CC398-MRSA-V (PVL+). CC96 belonged to CC96-MRSA-IV and CC96-MRSA-IV (PVL+) Central Asian caMRSA/WA MRSA-119. CC97 consisted of six strains including CC97-MRSA-V (fusC +), CC97-MRSA-IV WA MRSA-54/63, CC97-MRSA-V, CC97-MRSA-(V+fus), CC97-MRSA-(mec VI+fus), and CC97-MRSA (mecV/VT+fus+ccrAB2). Whereas CC96 and CC97 isolates were identified in 2016 and 2017, CC398 isolates were detected only in 2016. This study identified four LA-MRSA clones among MRSA isolated from patients in Kuwait hospitals in 2016-2017 with CC97-MRSA-V (fusC +) as the dominant clone. The presence of LA-MRSA with different genetic backgrounds suggests its independent acquisition from different sources.

Genetic lineages of community-associated methicillin-resistant Staphylococcus aureus in Kuwait hospitals.

Twenty-six community-associated methicillin-resistant Staphylococcus aureus (CAMSRA) isolates were characterized by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) and screened for accessory gene regulator (agr), capsular polysaccharide (cap), and Panton-Valentine leucocidin (PVL) genes. They exhibited five PFGE patterns (types A to E). The majority were PFGE type A (12 isolates) or type B (8 isolates). MLST showed that PFGE type A isolates belonged to sequence type 80 (ST80), while the PFGE type B isolates were ST30. The ST80 and ST30 clones contained agr allotype 3, cap type 8, and PVL. The results showed that two internationally recognized CAMRSA clones are dominant in Kuwait hospitals.

Emerging variants of methicillin-resistant Staphylococcus aureus genotypes in Kuwait hospitals.

BACKGROUND: Frequent changes in the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) occurring worldwide demand regular surveillance to study their composition and distribution in healthcare facilities. We investigated the genotypic characteristics of MRSA obtained in Kuwait hospitals to better understand their clonal distribution. MATERIALS AND METHODS: A total of 1,327 MRSA isolates obtained from clinical samples in 13 Kuwait hospitals from 1 January to 31 December 2016 were investigated using antibiogram, SCCmec typing, spa typing and DNA microarray. RESULTS: The isolates belonged to six SCCmec types with the majority belonging to type IV (658; 49.5%) and type V (355; 26.7%). Two hundred and sixty-one spa types were identified with spa types t688, t304, t860, t127, t044, t311, t002, t223, t267, t019, t3841, t005, t084, t852, and t657 constituting 51.0% (n = 677) of the isolates. Among the 1,327 MRSA isolates, 102 (7.68%) isolates were identified as novel variants of internationally recognized MRSA clones. These 102 isolates were investigated further and belonged to 14 clonal complexes (CCs) with CC361 (32; 32.3%), CC30 (15; 14.7%), CC22 (13; 12.7%) and CC1 (11, 10.7%) as the dominant CCs. Eighty-one (79.4%) of the novel isolates harbored SCCmec IV or V+fusC composite genetic elements. Four isolates (3.9%) harbored unusual combinations of ccr and mec complexes comprising of CC6-MRSA [IV+fusC+ccrC], CC97-MRSA [V/VT+fusC+ccrAB2], CC121-MRSA [V/VT+fusC+ccrB4] and CC1-MRSA-pseudoSCCmec [class B mec+fusc+ccrAB1]. Forty-six (45.1%) of these isolates were positive for PVL and 89 (87.2%) were resistant to fusidic acid mediated by fusC. CONCLUSIONS: The study showed the emergence of novel variants of previously recognized MRSA genotypes with unusual genetic characteristics including high prevalence of PVL and fusidic acid resistance in Kuwait hospitals. This has added to the dynamic lists of known variations in MRSA genomes which can impose serious challenges for infection control and treatment of MRSA infections.

Characterization of a CC1153 PVL-producing community-acquired methicillin-resistant Staphylococcus aureus from a dog bite wound.

The isolation of a rare community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) strain from an infected dog bite wound is here reported. A 27-year old man presented with a deep open wound on his right hand caused by his dog's bite at the outpatient clinic of Infectious Disease Hospital (IDH), Kuwait. A wound swab was obtained for bacteriological culture and susceptibility testing. The wound culture yielded pure heavy growth of an MRSA isolate, designated IDH70, which was susceptible to vancomycin, teicoplanin, erythromycin, clindamycin, trimethoprim, fusidic acid and rifampicin. The patient was successfully treated with a combination of rifampicin and cotrimoxazole twice daily for 10 days. Molecular characterization revealed that IDH70 was positive for genes encoding Panton-Valentine leucocidin. IDH70 also carried the SCCmec V genetic element, belonged to coagulase type XIIIa, spa type t903, and was assigned to clonal complex 1153 and sequence type ST1153 (ST1153-V-t903). The report highlights the increasing burden of CA-MRSA in the community and the risk of its acquisition from bites of companion animals.

Emergence of rifampicin resistance in methicillin-resistant Staphylococcus aureus isolated at a Turkish university hospital.

Twenty-three rifampicin-resistant methicillin-resistant Staphylococcus aureus (MRSA) isolated in three wards at a university hospital in Turkey between June, 2000, and February, 2001, were studied for their genetic relatedness using a combination of antibiogram, coagulase serotyping, coagulase gene polymorphism (coa-RFLP), and pulsed-field gel electrophoresis (PFGE). They all expressed high-level rifampicin resistance (MIC, >256 mg/L) and were resistant to gentamicin, kanamycin, amikacin, ciprofloxacin, tetracycline, and cadmium acetate and were susceptible to fusidic acid, vancomycin, trimethoprim, and mupirocin. They belonged to the same coagulase serotype (serotype IV) and had identical coa-RFLP patterns. In contrast, PFGE generated nine banding patterns designated type A, types A1-A5, B, C, and D. The most common PFGE pattern (type A) and its subtypes (types A1-A5) were seen in 20 (87%) of the 23 isolates in the three wards. The results demonstrated the acquisition of rifampicin resistance by different MRSA clones and the spread of one clone among patients in the three wards.

Transmission of a Klebsiella pneumoniae clone harbouring genes for CTX-M-15-like and SHV-112 enzymes in a neonatal intensive care unit of a Kuwaiti hospital.

The spread of antibiotic-resistant bacteria has become a large problem in most countries including Kuwait. This antibiotic resistance is usually due to the production of extended-spectrum beta-lactamase (ESBL) enzymes such as SHV, TEM and CTX-M. This study reports the emergence and spread of an ESBL-producing Klebsiella pneumoniae clone in a neonatal intensive care unit (NICU) in a Kuwaiti hospital. Eight ESBL-producing K. pneumoniae isolates were from blood cultures of seven neonates, and two were from the fingers of two healthcare workers in a NICU in Al Jahra Hospital, Kuwait. All isolates were obtained in February-March 2006, except for one, which was obtained in August 2005. Identification of the bacteria was based on traditional bacteriological and biochemical tests using the Vitek system. Antibiotic susceptibility was tested by the disc diffusion method using 16 different antibiotics. ESBLs were detected using disc approximation and double-disc synergy methods and confirmed as ESBLs using Etest. PCR and DNA sequencing were performed to determine the genotypes and mutations in the beta-lactamase genes (blaTEM, blaSHV and blaCTX-M). Genetic relatedness was determined by PFGE. All isolates were confirmed to have ESBLs by the Vitek system, disc approximation test, double-disc diffusion test and Etest, being resistant to cefotaxime, ceftazidime, cefepime, gentamicin, tobramycin and ciprofloxacin but susceptible to tetracycline and trimethoprim-sulfamethoxazole. Molecular studies showed the isolates to have TEM-1 beta-lactamase, a CTX-M-15-like ESBL and the newly discovered SHV-112 ESBL. PFGE showed that all isolates had identical banding patterns. The results indicate that a single clone of ESBL-producing K. pneumoniae caused bloodstream infections among babies in a NICU of a Kuwaiti hospital, and may have emerged at least 5 years ago. This clone was also present on the hands of healthcare workers, suggesting that they may have been involved in its transmission. Further studies are recommended to determine whether this clone is also spreading in other Kuwaiti hospitals.