Comparative in vitro activity of Delafloxacin and other antimicrobials against isolates from patients with acute bacterial skin, skin-structure infection and osteomyelitis.

The aim of this study was to compare the in vitro activity of delafloxacin with other fluoroquinolones against bacterial pathogens recovered from inpatients with osteomyelitis, Acute Bacterial Skin and Skin-Structure Infections (ABSSSI). In total, 100 bacterial isolates (58 % Gram-negative and 42 % Gram-positive) recovered from inpatients between January and April 2021, were reidentified at species level by MALDI-TOF MS. Antimicrobial susceptibility testing was conducted using the broth microdilution method and the detection of biofilm formation was assessed through the microtiter plate assay. The screening for mecA was carried out by PCR, while mutations in the Quinolone Resistance Determining Regions (QRDR), specifically gyrA and parC, were analyzed using PCR followed by Sanger sequencing. Results showed that delafloxacin exhibited greater in vitro potency (at least 64-times) than the other tested fluoroquinolones (levofloxacin and ciprofloxacin) when evaluating Staphylococcus aureus (MIC50 ≤0.008 mg/L) and coagulase-negative Staphylococcus (MIC50 0.06 mg/L). Furthermore, delafloxacin (MIC50 0.25 mg/L) was at least 4 times more potent than other tested fluoroquinolones (MIC50 1 mg/L) against P. aeruginosa. No difference in delafloxacin activity (MIC50 0.03 mg/L) was observed against Enterobacter cloacae when compared with ciprofloxacin (MIC50 0.03 mg/L). Despite presenting low activity against K. pneumoniae isolates (22.2 %), delafloxacin exhibited twice the activity compared to both levofloxacin and ciprofloxacin. Delafloxacin also exhibited a strong activity (71.4 %‒85.7 %.) against biofilm producing bacterial pathogens tested in this study. Interestingly, 82.14 % of the staphylococci tested in this study harbored mecA gene. In addition, the gyrA and parC genes in fluoroquinolone-resistant Gram-negative isolates displayed different mutations (substitutions and deletions). Herein, we showed that delafloxacin was the most active fluoroquinolone against staphylococci (including MRSA) and P. aeruginosa when compared to other fluoroquinolones such as ciprofloxacin and levofloxacin.

Co-resistance to methicillin and clindamycin among coagulase-negative staphylococci isolates recovered from pet food in Brazil.

Pet food have been considered as possible vehicles of bacterial pathogens. The sudden boom of the pet food industry due to the worldwide increase in companion animal ownership calls for pet food investigations. Herein, this study aimed to determine the frequency, antimicrobial susceptibility profile, and molecular characteristics of coagulase-negative staphylococci (CoNS) in different pet food brands in Brazil. Eighty-six pet food packages were screened for CoNS. All isolates were identified at species level by MALDI-TOF MS and species-specific PCR. Antimicrobial susceptibility testing was performed by disc diffusion and broth microdilution (vancomycin and teicoplanin only) methods. The D-test was used to screen for inducible clindamycin phenotype (MLS-B). SCCmec typing and detection of mecA, vanA, vanB, and virulence-encoding genes were done by PCR. A total of 16 (18.6 %) CoNS isolates were recovered from pet food samples. Isolates were generally multidrug-resistant (MDR). All isolates were completely resistant (100 %) to penicillin. Resistances (12.5 % - 75 %) were also observed for fluoroquinolones, sulfamethoxazole-trimethoprim, tetracycline, rifampicin, erythromycin, and tobramycin. Isolates were susceptible to vancomycin (MICs <0.25-1 µg/mL) and teicoplanin (MICs <0.25-4 µg/mL). Intriguingly, 3/8 (37.5 %) CoNS isolates with the ERYRCLIS antibiotype expressed MLS-B phenotype. All isolates harboured blaZ gene. Seven (43.8 %) isolates carried mecA; and among them, the SCCmec Type III was the most frequent (n = 5/7; 71.4 %). Isolates also harboured seb, see, seg, sej, sem, etb, tsst, pvl, and hla toxin virulence-encoding genes (6.3 % - 25 %). A total of 12/16 (75 %) isolates were biofilm producers, while the icaAB gene was detected in an S. pasteuri isolate. Herein, it is shown that pet food is a potential source of clinically important Gram-positive bacterial pathogens. To the best of our knowledge, this is the first report of MLS-B phenotype and MR-CoNS in pet food in Latin America.

Human Colonization and Infection by Staphylococcus pseudintermedius: An Emerging and Underestimated Zoonotic Pathogen.

S. pseudintermedius is a known resident of the skin and mucous membranes and a constituent of the normal microbiota of dogs. It has also been recognized as an opportunistic and zoonotic pathogen that is able to colonize humans and cause severe diseases, especially in immunocompromised hosts. Most importantly, methicillin-resistant S. pseudintermedius (MRSP), which is intrinsically multidrug-resistant, has emerged with serious public health consequences. The epidemiological situation is further exacerbated with reports of its zoonotic transmission and human infections which have been mostly attributed to the increasing frequency of dog ownership and close contact between dogs and humans. Evidence on the zoonotic transmission of MRSP from pet dogs to humans (such as dog owners, small-animal veterinarians, and other people in close proximity to dogs) is limited, especially due to the misidentification of S. pseudintermedius as S. aureus. Despite this fact, reports on the increasing emergence and spread of MRSP in humans have been increasing steadily over the years since its first documented report in 2006 in Belgium. The emergence of MRSP strains has further compromised treatment outcomes in both veterinary and human medicine as these strains are resistant to beta-lactam antimicrobials usually prescribed as first line treatment. Frustratingly, the limited awareness and surveillance of the zoonotic transmission of S. pseudintermedius have underestimated their extent of transmission, prevalence, epidemiology, and public health significance. In order to fill this gap of information, this review focused on detailed reports on zoonotic transmission, human colonization, and infections by S. pseudintermedius, their pathogenic features, antimicrobial resistance profiles, epidemiology, risk factors, and treatment. In writing this review, we searched Web of Science, PubMed, and SCOPUS databases using the keyword "Staphylococcus pseudintermedius AND humans". A phylogenetic tree to determine the genetic relatedness/diversity of publicly available genomes of S. pseudintermedius was also constructed.

Sequencing of fosA: A Rapid and Inexpensive Method for Discriminating Klebsiella pneumoniae CC258 from Other Clones.

Typing carbapenem-resistant Klebsiella pneumoniae (CR-KPN) is crucial in controlling their dissemination and solving outbreaks. In this context, we searched for an effective, faster, and cheaper alternative technique to type KPN by analyzing the fosAKP sequence. We analyzed the nucleotide sequences of chromosomal fosAKP gene in 350 KPN genomes (70 per sequence type [ST] or clonal complex [CC]). Assembly genomes were randomly downloaded from NCBI and annotated using RAST in PATRIC platform. The isolate STs were verified using multilocus sequence typing 2.0 by the Center for Genomic Epidemiology. Chromosomally encoded fosAKP was confirmed in MLplasmid, and the sequence alignments were performed in Clustal Omega. The amino acid sequences were analyzed using SNAP2 and SMART platforms. Out of the 70 genomes analyzed for each ST/CC, we observed 100% fosA sequence identity for CC258/11, ST15, ST307, and ST101. For ST16, only two fosA sequences were different from each other. We observed differences in amino acid sequences at positions 25 and 79 (ST16) and 86 (ST16, ST101). The C-terminal (amino acid 138, 139, 140) was different for each cluster. None of these polymorphisms is related to the protein active site. Moreover, L25Q (ST16) polymorphism was predicted to probably affect the protein function. We observed that chromosomal fosAKP sequences from KPN are highly conserved in ST15, ST307, ST16, ST101, and CC258/11, suggesting fosAKP sequencing as an alternative, easier, faster, and less expensive technique in identifying epidemiological STs for KPN, and discriminating them from CC258/11.