In Algeria, the issue of antibiotic resistance is on the rise, being the Staphylococcus aureus infection as a significant concern of hospital-acquired infections. The emergence of antibiotic resistance in this bacterium poses a worldwide challenge. The aim of this study aims to establish the incidence of S aureus strains in Algeria as well as identify phenotypic and genotypic resistance based on the \"mecA\" and \"nuc\" genes. From 2014 to 2017, a total of 185 S aureus strains were isolated from patients at a hospital in the city of Rouïba, Algiers the number of isolates was slightly higher in males at 58.06% compared to females at 41.94%, resulting in a sex ratio of 1.38. the Oxacillin and Cefoxitin DD test (1 μg oxacillin disk and 30 μg cefoxitin disk) identified 42 strains as resistant. The results indicated high resistance to lactam antibiotics, with penicillin having a 100% resistance rate. There was also significant resistance to oxacillin (51.25%) and cefoxitin (50%). This resistance was frequently associated with resistance to other antibiotic classes, such as aminoglycosides (50%) and Macrolides (28.29%). To confirm methicillin-resistant characteristics, a polymerase chain reaction (PCR) multiplex was conducted on 10 isolates (6 SARM; 4 MSSA) on a phenotypic level. Three isolates tested positive for \"mecA,\" while 7 were negative. All strains carry the nuc gene, which is specific to S aureus. In Algeria, the incidence of S aureus resistance is slightly lower compared to other countries, but it is increasing over time. It is now more crucial than ever to restrict the proliferation of multidrug-resistant strains and reduce undue antibiotic prescriptions. To achieve this, it is vital to keep updated on the epidemiology of this bacterium and its antibiotic susceptibility. This will enable the formulation of appropriate preventive control measures to manage its progression.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) poses a great health threat to humans. Looking for compounds that could reduce the resistance of S. aureus towards methicillin is an effective way to alleviate the antimicrobial resistance crisis.
RESULTS: Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), Time-killing growth curve, staphyloxanthin and penicillin-binding protein 2a (PBP2a) were detected. A quantitative polymerase chain reaction was used to measure the effect of BBH on the gene transcription profiles of MRSA. The MIC of MRSA-ST59-t437 towards oxacillin was 8 µg/ml, and MBC was 128 µg/ml. After adding a sub-inhibitory concentration of BBH, the MIC and MBC of MRSA-ST59-t478 towards oxacillin went down to 0.125 and 32 µg/ml respectively. The amount of PBP2a and staphyloxanthin were reduced after treatment with BBH. Moreover, the transcription levels of sarA, mecA and fni genes were downregulated.
CONCLUSIONS: It is for the first time reported that BBH could inhibit staphyloxanthin synthesis by inhibiting fni gene. Moreover, fni might be the target gene of sarA, and there might be another regulatory pathway to inhibit staphyloxanthin biosynthesis. BBH could effectively reduce the methicillin resistance of MRSA-ST59-t437 by downregulating fni, sarA and mecA genes.

Borderline oxacillin-resistant Staphylococcus aureus (BORSA) are mecA-negative strains with oxacillin minimum inhibitor concentration (MIC) close to the resistance breakpoint of ≥ 4μg/mL. Instead of producing penicillin-binding protein with low affinity to methicillin (oxacillin) mediated by mecA gene as in methicillin-resistant S. aureus (MRSA), BORSA strains are characterised by the hyperproduction of β-lactamase enzymes, thus able to break down methicillin. Common laboratory methods to detect MRSA such as cefoxitin disk diffusion alone may fail to detect methicillin resistance due to BORSA. We report five cases of BORSA blood-stream infections in a university teaching hospital. All isolates were found to be susceptible to cefoxitin using disk diffusion, resistant to oxacillin using automated MIC method, and did not harbour mecA gene. All patients were suscessfully treated with anti-MRSA antibiotics, and removal of primary sources were done if identified. A more cost-effective method for screening and diagnosis of BORSA is needed in addition to cefoxitin disk diffusion test, in order to monitor the spread, and to enable routine detection and treatment of this pathogen.

Methicillin-resistant Staphylococcus aureus (MRSA) has evolved into a dangerous pathogen resistant to beta-lactam antibiotics (BLAs) and has become a worrisome superbug. In this study, a strategy in which shikimic acid (SA), which has anti-inflammatory and antibacterial activity, is combined with BLAs to restart BLA activity was proposed for MRSA treatment. The synergistic effects of oxacillin combined with SA against oxacillin resistance in vitro and in vivo were investigated. The excellent synergistic effect of the oxacillin and SA combination was confirmed by performing the checkerboard assay, time-killing assay, live/dead bacterial cell viability assay, and assessing protein leakage. SEM showed that the cells in the control group had a regular, smooth, and intact surface. In contrast, oxacillin and SA or the combination treatment group exhibited different degrees of surface collapse. q-PCR indicated that the combination treatment group significantly inhibited the expression of the mecA gene. In vivo, we showed that the combination treatment increased the survival rate and decreased the bacterial load in mice. These results suggest that the combination of oxacillin with SA is considered an effective treatment option for MRSA, and the combination of SA with oxacillin in the treatment of MRSA is a novel strategy.

With the widespread use of antibiotics, the incidence of antibiotic resistance in microorganisms has increased. Monochamus alternatus is a trunk borer of pine trees. This study aimed to investigate the in vitro antimicrobial and biological characteristics of Enterococcus casseliflavus TN-47 (PP411196), isolated from the gastrointestinal tract of M. alternatus in Jilin Province, PR China. Among 13 isolates obtained from the insects, five were preliminarily screened for antimicrobial activity. E. casseliflavus TN-47, which exhibited the strongest antimicrobial activity, was identified. E. casseliflavus TN-47 possessed antimicrobial activity against Staphylococcus aureus USA300 and Salmonella enterica serovar Pullorum ATCC 19945. Furthermore, E. casseliflavus TN-47 was sensitive to tetracyclines, penicillins (ampicillin, carbenicillin, and piperacillin), quinolones and nitrofuran antibiotics, and resistant to certain beta-lactam antibiotics (oxacillin, cefradine and cephalexin), macrolide antibiotics, sulfonamides and aminoglycosides. E. casseliflavus TN-47 could tolerate low pH and pepsin-rich conditions in the stomach and grow in the presence of bile acids. E. casseliflavus TN-47 retained its strong auto-aggregating ability and hydrophobicity. This strain did not exhibit any haemolytic activity. These results indicate that E. casseliflavus TN-47 has potential as a probiotic. This study provides a theoretical foundation for the future applications of E. casseliflavus TN-47 and its secondary metabolites in animal nutrition and feed.

UNASSIGNED: Antimicrobial resistance poses a significant global threat to the treatment of bacterial infections, particularly in low- and middle-income regions such as Africa. This study is aimed at analyzing antimicrobial resistance patterns in vaginal swab samples from patients at the National Health Laboratory from 2019 to 2022.
UNASSIGNED: This retrospective study examined patient records from vaginal swab analyses performed at the National Health Laboratory between January 1, 2019, and December 31, 2022. Ethical approval was obtained from the Ministry of Health Research Ethical Approval and Clearance Committee on 15/02/2023.
UNASSIGNED: Of the 622 samples, 83% underwent microbial isolation and identification. Citrobacter spp. exhibited high resistance (>43%) to antibiotics such as cephalexin, ceftazidime, nalidixic acid, ampicillin, gentamicin, and tetracycline. E. coli showed resistance rates of more than 50% to ampicillin, trimethoprim-sulfamethoxazole, and tetracycline. Klebsiella spp. and Proteus spp. exhibited resistance rates that exceeded 47% to specific antibiotics. Gram-positive bacteria have resistance rates of more than 49% with ampicillin, trimethoprim-sulfamethoxazole, tetracycline, oxacillin, vancomycin, and penicillin G. In particular, S. aureus demonstrated no resistance to rifampicin or clindamycin, while Streptococcus spp. showed 100% resistance to rifampicin and vancomycin. Several species, including Proteus species, Streptococcus spp., S. aureus, and Klebsiella spp. exhibited multidrug resistance.
UNASSIGNED: Most gram-negative bacteria displayed higher resistance of >45% to ampicillin, trimethoprim-sulfamethoxazole, and tetracycline. Among gram-positive bacteria, a higher resistance rate with ampicillin, trimethoprim-sulfamethoxazole, tetracycline, oxacillin, vancomycin, and penicillin G was recorded. S. aureus showed no resistance to rifampicin and clindamycin, and Strep. spp. indicated 100% resistance to rifampicin and vancomycin. This study highlights critical gaps and areas for further exploration. Expanding the spectrum of antibiotics tested and investigating underlying multidrug resistance mechanisms would provide a more comprehensive understanding of resistance patterns.

Ruminant mastitis continues to be a cause of economic losses in the dairy industry and remains a major public health hazard globally.
This cross-sectional study was carried out in Mukurweini Sub-County of Nyeri County, Kenya, to investigate the prevalence of bacteria causing mastitis, risk factors associated with goat mastitis and the antibiotic resistance profiles of bacteria isolated from the goat milk.
Farm level data on risk factors for mastitis was obtained from 56 farmers using a semi structured questionnaire. A total of 189 goat milk samples were collected. The goat\'s udder was observed for signs of clinical mastitis and the California Mastitis Test (CMT) used to test the milk for sub-clinical mastitis. All samples were then cultured for morphological identification of bacteria and strain typing by Matrix Assisted Laser Desorption/Ionization (MALDI)-Time of Flight (ToF) technique. Antimicrobial susceptibility of the isolated Staphylococcus aureus, coagulase-negative Staphylococcus (CoNS), Escherichia coli, Klebsiella oxytoca, Pseudomonas spp., Enterobacter spp., Proteus vulgaris and Escherichia vulneris to eight commonly used antibiotics was done by the disc diffusion method and validated by determining the presence of antibiotic resistance genes (mecA and blaTEM) using polymerase chain reaction method.
The prevalence of clinical mastitis was 1.1% (2/189) while that of sub-clinical mastitis was 84.7% (160/189). Higher (p < 0.05) prevalence of mastitis was observed in goats whose houses were cleaned fortnightly and in cases where farmers used same towel to dry different does\' udders during the milking process. Thirteen different bacterial species were isolated from the milk samples and identified by MALDI-ToF, and these included S. aureus (22.0%), CoNS (20.3%), E. coli (18.1%), Pseudomonas spp. (14.3%), Enterobacter spp. (10.4%), K. oxytoca (6.0%), E. vulneris (1.7%), P. vulgaris (1.7%), Raoutella ornithinolytica (1.7%), Stenotrophomonas maltophilia (1.1%), Pantoea agglomerans (1.1%), Serratia marcescens (1.1%) and Cedeceas spp. (0.6%). One hundred pathogenic bacterial isolates were randomly selected and tested for antibiotic sensitivity to eight antibiotics out of which S. aureus were 97.5% resistant to Oxacillin and 100% sensitive to Ciprofloxacin. The CoNSs were 100% resistant to Oxacillin and 100% sensitive to Ciprofloxacin. E. coli were 93.9% resistant to Oxacillin, 69.7% sensitive to Ciprofloxacin and 87.9% sensitive to both Amoxicillin/Clavulanic acid and Meropenem. The antimicrobial resistant genes detected in S. aureus and E. coli were mecA [66.7%, 0%], and blaTEM [20% and 78.3%], respectively.
In conclusion, the study showed that most of the does were affected by subclinical mastitis with the main causative bacteria being Staphylococci spp. and coliforms. Farmers need to be trained on improved control of mastitis by adoption of good milking practices and use of CMT kit for early detection of mastitis. Occurrence of multidrug resistance by key mastitis causing pathogens was shown to be prevalent and therefore there is need for development of intervention strategies.

OBJECTIVE: The purpose was to evaluate the antimicrobial activity of highly soluble polypyrrole (Hs-PPy), alone or combined with oxacillin, as well as its antibiofilm potential against methicillin-resistant Staphylococcus aureus strains. Furthermore, the in silico inhibitory mechanism in efflux pumps was also investigated.
RESULTS: Ten clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) and two reference strains were used. Antimicrobial activity was determined by broth microdilution, and the combination effect with oxacillin was evaluated by the checkerboard assay. The biofilm formation capacity of MRSA and the interference of Hs-PPy were evaluated. The inhibitory action of Hs-PPy on the efflux pump was evaluated in silico through molecular docking. Hs-PPy showed activity against the isolates, with inhibitory action between 62.5 and 125 µg ml-1 and bactericidal action at 62.5 µg ml-1, as well as synergism in association with oxacillin. The isolates ranged from moderate to strong biofilm producers, and Hs-PPy interfered with the formation of this structure, but not with mature biofilm. There was no in silico interaction with the efflux protein EmrD, the closest homolog to NorA.
CONCLUSIONS: Hs-PPy interferes with biofilm formation by MRSA, has synergistic potential, and is an efflux pump inhibitor.

BACKGROUND: Multidrug resistance in Staphylococcus aureus continues to influence treatment complications in clinical settings globally. Multidrug-resistant-S. aureus (MDR-SA) is often genetically driven by resistance markers transferable in pathogenic strains. This study aimed to determine the distribution of resistance markers in clinical isolates of S. aureus in Nsukka, Nigeria.
METHODS: A total of 154 clinical samples were cultured on mannitol salt agar. Isolates were characterized using conventional cultural techniques and confirmed by PCR detection of S. aureus-specific nuc gene. Antibiotic resistance profiles of the isolates were determined against selected antibiotics using the disk-diffusion method, while screening for antibiotic resistance genes (Mec A, Erm A, Erm B, Erm C, Van A, and Van B) was by PCR.
RESULTS: A total of 98 isolates were identified as S. aureus by conventional methods. Of these, 70 (71.43%) were confirmed by PCR. Phenotypically, the isolates exhibited high degrees of resistance to oxacillin (95.72%), erythromycin (81.63%), and ertapenem (78.57%) and 75.51% and 47.30% against methicillin and vancomycin, respectively. Multiple antibiotic resistance indexes of the isolates ranged from 0.3 to 1, and the most prevalent pattern of resistance was oxacillin-ertapenem-vancomycin-erythromycin-azithromycin-clarithromycin-ciprofloxacin- cefoxitin-amoxicillin-clavulanic acid. PCR screening confirmed the existence of various antibiotic resistance makers among the strains, with the most common resistance genes found in the isolates being Mec A (32.14%), Van A (21.43%), Van B (10.71%), Erm B (10.71%), and Erm C (17.86%). None possessed the Erm A gene.
CONCLUSIONS: The study supports the need for necessary action, including rational drug use, continuous surveillance, and deployment of adequate preventive and curative policies and actions.

OBJECTIVE: Doxycycline post exposure prophylaxis (PEP) has been shown to reduce the incidence of bacterial STIs. However, if there is genetic linkage between resistance to tetracycline and other antimicrobials, then it could also select for resistance to these other antimicrobials. We therefore undertook to evaluate if there is an association between the minimum inhibitory concentrations (MICs) of tetracycline and other antimicrobials in 19 clinically important bacterial species.
METHODS: Mixed-effects linear regression was used to assess if minocycline MICs were associated with the MICs of eight other antimicrobials (ceftriaxone, ampicillin, oxacillin, vancomycin, erythromycin, levofloxacin, amikacin, and trimethoprim-sulfamethoxazole) in 19 bacterial species in the Antimicrobial Testing Leadership and Surveillance (ATLAS) database.
RESULTS: With the notable exception of vancomycin, where no association was found, strong positive associations were typically found between the MICs of minocycline and each of the eight antimicrobials in each of the species assessed. For example, the minocycline MICs of all the Gram-positive species were positively associated with ampicillin, ceftriaxone, oxacillin and erythromycin MICs (all P-values < 0.001). The only exceptions were ampicillin for Streptococcus pyogenes and ceftriaxone for S. dysgalactiae, where no significant associations were found. Similarly in the Gram-negative species, the minocycline MICs of all the species except Haemophilus influenzae and Stenotrophomonas maltophilia were positively associated with the MICs of ceftriaxone, ampicillin, levofloxacin and amikacin (all P-values < 0.001).
CONCLUSIONS: There is a theoretical risk that doxycycline PEP could select for resistance not only to tetracyclines but to a range of other antimicrobials in each of the 19 pathobionts assessed.