Detection and characterization of potential virulence determinants in Staphylococcus pseudintermedius and S. schleiferi strains isolated from canine otitis externa in Korea.

BACKGROUND: A recent increase in the occurrence of canine skin and soft tissue infections, including otitis externa and pyoderma, caused by antimicrobial-resistant Staphylococcus pseudintermedius and S. schleiferi has become a significant public and veterinary health issues. OBJECTIVE: We investigated the virulence potentials associated with the occurrence of canine otitis externa in S. pseudintermedius and S. schleiferi. METHODS: In this study, the prevalence of genes encoding leukocidins, exfoliative toxins, and staphylococcal enterotoxins (SEs) was investigated using previously characterized S. pseudintermedius (n = 26) and S. schleiferi (n = 19) isolates derived from canine otitis externa. Susceptibility to cathelicidins (K9CATH and PMAP-36) and hydrogen peroxide (H2O2) was also examined in both staphylococcal species. RESULTS: A high prevalence of genes encoding leukocidins (lukS/F-I, lukS1/F1-S, and lukS2/F2-S), exfoliative toxins (siet, expB, and sset), and SEs was identified in both S. pseudintermedius and S. schleiferi isolates. Notably, S. pseudintermedius isolates possessed higher number of SE genes, especially newer SE genes, than S. schleiferi isolates harboring egc clusters. Although no significant differences in susceptibility to K9CATH and H2O2 were observed between the two isolate groups, S. pseudintermedius isolates exhibited enhanced resistance to PMAP-36 compared to S. schleiferi isolates. CONCLUSIONS: These findings suggest that high a prevalence of various toxin genes together with enhanced resistance to cathelicidins may contribute to the pathogenicity of S. pseudintermedius and S. schleiferi in canine cutaneous infections.

Clonal distribution and antimicrobial resistance of methicillin-susceptible and -resistant Staphylococcus aureus strains isolated from broiler farms, slaughterhouses, and retail chicken meat.

Colonization of food-producing animals by antimicrobial-resistant Staphylococcus aureus, especially methicillin-resistant S. aureus (MRSA), has become a serious public health problem worldwide. In the current study, clonal diversities of livestock-associated S. aureus isolates collected from broiler farms, slaughterhouses, and retail chicken meat were examined. Two-hundred S. aureus isolates (43 MRSA and 157 methicillin-susceptible S. aureus [MSSA] isolates) were analyzed to determine 1) the genotypes of the isolates (multilocus sequence, agr, and spa types), 2) the methicillin resistance phenotype and staphylococcal cassette chromosome mec (SCCmec) types, 3) the antimicrobial resistance profiles, and 4) the mutational changes in gyrA, gyrB, parC, and parE in fluoroquinolone-resistant isolates. Fifteen different sequence types (STs) of MSSA strains displaying a relatively high degree of genetic diversity were detected in broiler farms, slaughterhouses, and retail chicken meat. In contrast to MSSA, 2 dominant genetic lineages of MRSA (ST692-SCCmecV with t2249 spa type, and ST188-SCCmecIVa with spa type t189) were found in healthy broilers. The high prevalence of ST692 and ST188 in healthy broilers is associated with high levels of multiple antimicrobial-resistance phenotypes, particularly fluoroquinolone resistance. All fluoroquinolone-resistant isolates carried double point mutations in gyrA (S84L) and parC (S80F), regardless of STs or methicillin resistance. Notably, only the ST188 lineage carried an additional third mutation in gyrB (D494N), correlating with enhanced ciprofloxacin minimum inhibitory concentration values versus the strains with double mutations. These results provide important insights into the genetic diversity of antimicrobial-resistant S. aureus strains associated with the chicken meat production chain, including healthy broilers, in Korea.

Multilocus sequence type-dependent activity of human and animal cathelicidins against community-, hospital-, and livestock-associated methicillin-resistant Staphylococcus aureus isolates.

Sequence type (ST) 5 methicillin-resistant Staphylococcus aureus (MRSA) with staphylococcal cassette chromosome mec (SCCmec) type II (ST5-MRSA-II) and ST72-MRSA-IV represent the most significant genotypes for healthcare- (HA) and community-associated (CA) MRSA in Korea, respectively. In addition to the human-type MRSA strains, the prevalence of livestock-associated (LA) MRSA clonal lineages, such as ST541 and ST398 LA-MRSA-V in pigs and ST692 LA-MRSA-V and ST188 LA-MRSA-IV in chickens, has recently been found. In this study, clonotype-specific resistance profiles to cathelicidins derived from humans (LL-37), pigs (PMAP-36), and chickens (CATH-2) were examined using six different ST groups of MRSA strains: ST5 HA-MRSA-II, ST72 CA-MRSA-IV, ST398 LA-MRSA-V, ST541 LA-MRSA-V, ST188 LA-MRSA-IV, and ST692 LA-MRSA-V. Phenotypic characteristics often involved in cathelicidin resistance, such as net surface positive charge, carotenoid production, and hydrogen peroxide susceptibility were also determined in the MRSA strains. Human- and animal-type MRSA strains exhibited clonotype-specific resistance profiles to LL-37, PMAP-36, or CATH-2, indicating the potential role of cathelicidin resistance in the adaptation and colonization of human and animal hosts. The ST5 HA-MRSA isolates showed enhanced resistance to all three cathelicidins and hydrogen peroxide than ST72 CA-MRSA isolates by implementing increased surface positive charge and carotenoid production. In contrast, LA-MRSA strains employed mechanisms independent of surface charge regulation and carotenoid production for cathelicidin resistance. These results suggest that human- and livestock-derived MRSA strains use different strategies to counteract the bactericidal action of cathelicidins during the colonization of their respective host species.

Profiles of Non-aureus Staphylococci in Retail Pork and Slaughterhouse Carcasses: Prevalence, Antimicrobial Resistance, and Genetic Determinant of Fusidic Acid Resistance.

As commensal colonizers in livestock, there has been little attention on staphylococci, especially non-aureus staphylococci (NAS), contaminating meat production chain. To assess prevalence of staphylococci in retail pork and slaughterhouse carcass samples in Korea, we collected 578 samples from Korean slaughterhouses (n=311) and retail markets (n=267) for isolation of staphylococci and determined antimicrobial resistance phenotypes in all the isolates. The presence of and prevalence of fusB-family genes (fusB, fusC, fusD, and fusF) and mutations in fusA genes were examined in fusidic acid resistant isolates. A total of 47 staphylococcal isolates of 4 different species (Staphylococcus aureus, n=4; S. hyicus, n=1; S. epidermidis, n=10; Mammaliicoccus sciuri, n=32) were isolated. Fusidic acid resistance were confirmed in 9/10 S. epidermidis and all of the 32 M. sciuri (previously S. sciuri) isolates. Acquired fusidic acid resistance genes were detected in all the resistant strains; fusB and fusC in S. epidermidis and fusB/C in M. sciuri. Multi-locus sequence type analysis revealed that ST63 (n=10, 31%) and ST30 (n=8, 25%) genotypes were most prevalent among fusidic acid resistant M. sciuri isolates. In conclusion, the high prevalence of fusB-family genes in S. epidermidis and M. sciuri strains isolated from pork indicated that NAS might act as a reservoir for fusidic acid resistance gene transmissions in pork production chains.

Species Distribution, Antimicrobial Resistance, and Enterotoxigenicity of Non-aureus Staphylococci in Retail Chicken Meat.

Non-aureus staphylococci (NAS), including coagulase-negative staphylococci, have emerged as important causes of opportunistic infections in humans and animals and a potential cause of staphylococcal food poisoning. In this study, we investigated (i) the staphylococcal species profiles of NAS in in retail chicken meat, (ii) the phenotypic and genotypic factors associated with antimicrobial resistance in the NAS isolates, and (iii) the prevalence of classical and newer staphylococcal enterotoxin (SE) genes. A total of 58 NAS of nine different species were isolated from retail raw chicken meat samples. The occurrence of multidrug resistance in the NAS, particularly S. agnetis and S. chromogenes, with high resistance rates against tetracycline or fluoroquinolones were confirmed. The tetracycline resistance was associated with the presence of tet(L) in S. chromogenes and S. hyicus or tet(K) in S. saprophyticus. The occurrence of fluoroquinolone resistance in S. agnetis and S. chromogenes was usually associated with mutations in the quinolone resistance determining regions (QRDR) of gyrA and parC. In addition, the frequent presence of SE genes, especially seh, sej, and sep, was detected in S. agnetis and S. chromogenes. Our findings suggest that NAS in raw chicken meat can have potential roles as reservoirs for antimicrobial resistance and enterotoxin genes.

Conservative treatment using a sponge cast for transfer fractures in nursing home patients.

BACKGROUND: Transfer fractures in the lower limbs of bedridden and chair-bound nursing home patients can result from trauma induced by the usual lifting, moving, turning, or transferring maneuvers. Treatment entails immobilization for pain control and position change; however, splints/hard casts increase the risk of pressure sores. Therefore, we evaluated the use of a sponge cast. MATERIALS AND METHODS: Between March 2011 and October 2017, 17 patients with a lower limb transfer fracture due to transferring maneuvers in a nursing home were recruited. We evaluated the improvement in pseudo-motion and divided the patients as having bony union, fibrous union, or remaining pseudo-motion. We also investigated the occurrence of pressure sores due to immobilization up until the final follow-up. RESULTS: Femur fractures occurred in 15 patients and lower leg fractures in two. Six of the 15 femur fractures were periprosthetic (four hip arthroplasty and two knee arthroplasty). Pseudo-motion was improved in 15 of 17 cases, within an average of 17.3 weeks for the improvement (14-23 weeks; bony union: 11 cases and fibrous union: four cases). Pseudo-motion remained in two cases: one periprosthetic fracture around the knee arthroplasty and the other, a femur neck fracture. No pressure sores occurred. CONCLUSIONS: A sponge cast appears to be one of the effective treatment options available for bedridden or chair-bound patients with a lower limb fracture due to its low risk of complications and satisfactory clinical results.

Bilateral Avascular Necrosis of the Femoral Head in a Patient with Asymptomatic Adrenal Incidentaloma.

Except when caused by direct and definite mechanisms (e.g., injury of the vessels to the femoral head), the pathophysiology of avascular necrosis of the femoral head has not yet been fully elucidate. While non-traumatic avascular necrosis of the femoral head is known to be caused by alcohol, steroids and various diseases, it may also occur without such events in a patient's history. Herein, a case of bilateral avascular necrosis of the femoral head caused by asymptomatic adrenal cortex incidentaloma which was initially misdiagnosed as idiopathic is reported along with a literature review.

Effect of surgical approach for contralateral side hip arthroplasty in below knee amputees: a retrospective cohort study.

BACKGROUND: The gluteus medius muscle plays a very important role in the stability of the gait, especially in patients with amputation of the lower limbs. Therefore, choosing the appropriate type of approach for hip arthroplasty is very important. Hence, this study aimed to compare the outcomes and complications between the anterolateral approach (ALA) and posterior approach (PA) for hip arthroplasty in patients with contralateral below knee amputation. METHODS: From January 1999 to November 2014, 67 patients who underwent hip arthroplasty with contralateral below knee amputation were retrospectively analyzed. The study subjects were divided into two groups: the PA group (33 cases) and the ALA group (34 cases). The results of the clinical functional recovery with Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, Harris Hip Score, and activity of daily living scale were compared between the two groups. During the follow-up period, complications related to gait such as fall, dislocation, and periprosthetic fractures (PPFs) were investigated. RESULTS: The Harris Hip Score (p = 0.024) and the activity of the daily living scale (p = 0.043) of the ALA group were significantly lower at 3 months compared to the PA group, but no significant difference was observed between the two groups from 6 months postoperatively to the last follow-up. The WOMAC score was not significantly different between the two groups. Within 3 months after surgery, falls occurred in 3 cases in the PA group and in 11 cases in the ALA group (p = 0.019) Dislocation and PPF were caused by prosthesis-related trauma. Two dislocations and 1 PPF occurred 8 years postoperatively in the PA group. PPF occurred in 3 patients in the ALA group, of which 2 occurred within 3 months after surgery. CONCLUSION: Orthopedic surgeons should pay particular attention in patients with hip arthroplasty on the contralateral side hip who had below knee amputation because functional recovery is delayed until 3 months after ALA compared with PA.