Background and Aim: Extended-spectrum β-lactamase (ESBL) is an enzyme produced by the family of Enterobacteriaceae, especially Escherichia coli and Klebsiella pneumoniae, which can hydrolyze β-lactam antibiotics, such as penicillins, cephalosporins, cephamycin, and carbapenem. ESBL-producing bacteria are widely distributed from farms to slaughterhouses until food products originating from animals are available in the market, which plays an important role as a pathway for the exposure and transmission of ESBL-producing bacteria from food products of animal origin to humans. This study aimed to determine the antibacterial activity of Syzygium aromaticum (clove) and Cinnamomum verum (cinnamon) essential oils against strains resistant to ESBL-producing E. coli and K. pneumoniae isolates. Materials and Methods: The antibacterial activity of clove and cinnamon essential oils was tested against three strains of tested bacteria using the disk diffusion method. The minimum inhibitory concentration (MIC) of clove and cinnamon essential oils was determined using the broth microdilution method. The minimum bactericidal concentration (MBC) was determined using the MIC. Morphological changes on each tested bacteria were observed through scanning electron microscopy (SEM). Results: Both essential oils exhibited inhibitory effects toward all test organisms, indicated by inhibition zones around the disk. The MIC values of clove essential oil were 0.078% (v/v) for all tested bacteria, whereas the MICs of cinnamon essential oil ranged from 0.039% (v/v) to 0.156% (v/v) for all tested bacteria. MBC values of clove and cinnamon essential oils ranged from 0.078% (v/v) to 0.156% (v/v) for all tested bacteria. There were morphological changes in each tested bacterial cell that was observed through SEM. Each tested bacteria treated with clove and cinnamon essential oils showed shrinkage and cells lysis. Conclusion: It was concluded that clove and cinnamon essential oils have emerged as effective antibacterial agents by showing high antibacterial activity against ESBL-producing E. coli and K. pneumoniae isolates, as evidenced by the inhibition zone diameter and MIC value.

Nurhikmayani R, Daryono BS, Retnaningrum E. 2019. Isolation and molecular identification of antimicrobial-producing Lactic Acid Bacteria from chao, South Sulawesi (Indonesia) fermented fish product. Biodiversitas 20: 1063-1068. Chao is traditional fermented fish made of anchovy (Stolephorus sp.), rice, salt, and fermented naturally on controlled environment. The product comes from Pangkep Regency, South Sulawesi. Chao has the potential for the source of high-grade lactic acid bacteria isolates, especially for antimicrobial compound. Antimicrobial compound produced by lactic acid bacteria is a biopreservative compound with many advantages. The purposes of this investigation were to isolate antimicrobial-producing lactic acid bacteria from chao and to identify their isolates based on the molecular properties. Lactic acid bacteria were isolated from chao using Man Ragosa Sharpe Agar (MRSA) medium added with 0.1 % CaCO3, followed by the ability test to produce antimicrobial compound against Staphylococcus aureus FNCC 0047 as an indicator. The spectrum of crude antimicrobial as cell-free supernatant (CFS) was determined by antagonism against S. aureus FNCC 0047 and Escherichia coli FNCC 0049 on agar well diffusion test. Selected isolates of antimicrobial-producing lactic acid bacteria molecularly identified from 16S rRNA marker using primer 27F and 1492R. We obtained four isolates of lactic acid bacteria that showed the antimicrobial activity. This crude antimicrobial compound could inhibit both gram-positive Staphylococcus aureus FNCC0047 and gram-negative bacteria Escherichia coli FNCC0049. The highest crude antimicrobial activity of isolates was observed on IB1C strain. The results of molecular characterization suggested that the IB1C and IB3B strain were identified as Lactobacillus plantarum, whereas IB3E and IB3F were identified as Pediococcus pentosaceus.

The emergence of multidrug-resistant (MDR) infections in wounds is a significant public health issue. The aim of this study was to investigate the prevalence and antimicrobial resistance profiles of MDR bacterial isolates in wound infections. Through a cross-sectional study, 1035 bacterial isolates were collected from wound infection patients at Tugurejo Hospital in Semarang, Indonesia, over a three-year period (January 2020 to December 2022). Initial identification involved Gram staining and colony morphology assessment, followed by biochemical assays and antimicrobial susceptibility testing using the VITEK®2 Compact system. Gram-negative bacteria constituted the majority of isolates (60.77%, n=629). The predominant strains included were Staphylococcus spp. (30.92%, n=320), Escherichia coli (18.45%, n=191), and Klebsiella pneumoniae (13.04%, n=135). Notably, Gram-negative bacteria exhibited a significantly higher likelihood of MDR development compared to their Gram-positive counterparts (p<0.001), with Gram-negative bacteria having a 2.05 times higher probability of acquiring MDR. These findings underscore the urgent need for comprehensive surveillance of antimicrobial resistance patterns and the implementation of tailored antimicrobial stewardship programs to address the pressing public health challenge of MDR wound infections. Further research is warranted to elucidate the complex interplay of factors contributing to MDR development in wound infections, thereby informing targeted intervention strategies and improving patient outcomes.

Bakteri asam laktat (BAL) dapat memberikan manfaat dan aman untuk dikonsumsi manusia. Bakteri ini menghasilkan metabolit sekunder yang berpotensi menghasilkan eksopolisakarida (EPS). Bakteri asam laktat ditemukan pada buah-buahan salah satunya buah kersen (Muntingia calabura L.). Kandungan karbohidrat yang tinggi dalam buah ini cocok untuk pertumbuhan BAL. Penelitian ini bertujuan untuk mengetahui keberadaan bakteri asam laktat beserta karakter fenotipik dan mengetahui potensinya dalam menghasilkan eksopolisakarida. Isolat bakteri asam laktat diperoleh dengan cara inokulasi suspensi buah kersen ke dalam medium MRS (de Man Rogosa Sharpe). Isolat bakteri asam laktat yang diperoleh kemudian dikarakterisasi fenotipik berdasarkan morfologi koloni, sel, sifat biokimiawi, dan fisiologis. Sebanyak empat isolat BAL diperoleh dengan bentuk sel basil, gram positif, katalase negatif, non-motil, non spore forming, mesofilik, aciduric, non halofilik serta dapat memfermentasi karbohidrat. Berdasarkan Bergey’s Manual of Systematic Bacteriology keempat isolat teridentifikasi sebagai spesies Lactobacillus plantarum. Keempat isoalat juga menunjukkan kemampuan menghasilkan eksopolisakarida dengan kisaran 870-1.910 mg/L.

Retnaningrum E, Yossi T, Nur'azizah R, Sapalina F, Kulla PDK. 2020. Characterization of a bacteriocin as biopreservative synthesized by indigenous lactic acid bacteria from dadih soya traditional product used in West Sumatra, Indonesia. Biodiversitas 21: 4192-4198. A total of 4 isolates of lactic acid bacteria (strain BDL08, BDL11, BDL12, and BDL13) isolated from dadih soya were investigated for the ability to produce bacteriocin based on their antibacterial activities against Listeria monocytogenes ATCC 7644. Based on comparative 16S rDNA sequencing analysis, isolates BDL 11, BDL12, and BDL13 were identified as Lactobacillus plantarum while the isolates BDL 08 was identified as Leuconostoc mesenteroides. All crude bacteriocins producing strains revealed broad antibacterial spectrum against 7 different indicator bacteria, including Gram-positive and Gram-negative bacteria. L. plantarum BDL11 displayed the highest bacteriocin activity relative to others. The bacteriocin produced by the strain was not affected by pH, heating, and NaCl concentration but was sensitive to proteolytic enzymes. This research indicated that the bacteriocin in the food industry has the potential to be used as a biopreservative.

Soleha S, Retnaningrum E. 2020. Screening and molecular identification of lipolytic bacteria from spent bleaching earth. Biodiversitas 21: 4155-4161. Lipolytic bacteria can produce nanobioremediation materials that encourage researchers to explore the diversity of these bacteria. Lipolytic bacteria were isolated from spent bleaching earth (SBE). Bacteria isolates were screened for their lipolytic index and crude lipase activity. Strain with the highest lipolytic index and crude lipase activity were identified using the 16S rRNA gene as genetic markers. The maximum likelihood method in MEGA6 software has been used to analyze the relationship of the isolate. The results showed that strain SBE01 had the highest lipolytic index and crude lipase activity of 8.8 ± 0.7 mm and 5.7 U/mL, respectively. Based on 16S rRNA gene analysis, the isolate was identified as Moraxella sp. Phylogenetic tree was shown that SBE01 isolate was closely related to Moraxella osloensis. Moraxella sp. has the potential to be used as a bioremediation agent from oil-contaminated environment.