Antibacterial activity of Lagerstreomia speciosa and its active compound, corosolic acid, enhances cefotaxime inhibitory activity against Staphylococcus aureus

AIMS

Various epidemiology studies have reported the emergence of Staphylococcus aureus and its methicillin resistance strain causing global health concerns, especially during and post-COVID-19 pandemic. This pathogen presents as a co-infection in patients with COVID-19. In addition, certain virulence factors and resistance to β-lactam antibiotics, including cefotaxime, have been identified. We aimed to investigate the antibacterial activity of Lagerstreomia speciosa, a medicinal plant with antidiabetic activity, against S. aureus, including the strain resistant to methicillin. Furthermore, we examined whether the extract and one of its bioactive compounds, corosolic acid, can enhance the therapeutic effect of cefotaxime on antibiotic-resistant S. aureus.

METHODS AND RESULTS

The minimum inhibitory concentration of each substance was determined using the standard broth microdilution test following the checkerboard dilution. The type of interactions, synergistic, additivity, indifference, or antagonism, were determined using isobolograms analysis and the dose reduction index (DRI). The evaluation of synergy and bactericidal activity of the natural products in combination with cefotaxime was performed using the time-kill kinetic assay. Corosolic acid, L. speciosa leaves extract, and bark extract alone showed antibacterial activity against all tested S. aureus ATCC 33591, S. aureus ATCC 29213, S. aureus ATCC 25923, and clinical isolated S. aureus. Corosolic acid enhanced the antibacterial activity of cefotaxime, showing a synergistic effect and greater DRI of cefotaxime against all tested S. aureus strains. Time-kill kinetic assay showed that corosolic acid has a more profound effect than L. speciosa extracts to potentiate the bactericidal activity of cefotaxime. Whereas L. speciosa leaves and bark extract showed some inhibitory effect on the growth of S. aureus after a single administration.

CONCLUSIONS

Lagerstreomia speciosa leaves and bark extract and its active compound, corosolic acid, could be used as a potential anti-Staphylococcus aureus treatment to enhance the therapeutic use of cefotaxime.

Synergistic Effect and Time-Kill Evaluation of Eugenol Combined with Cefotaxime Against Staphylococcus aureus

Eugenol, a clove-derived aromatic compound has shown antibacterial activity against many species, including Staphylococcus aureus. Epidemiology studies from the past two decades reported an increased number of healthcare-associated and skin tissue infections due to S. aureus antimicrobial resistance (AMR) including several cases of resistance to β-lactam antibiotics, such as cefotaxime. We aimed to investigate whether eugenol can cause lethality of S. aureus including the strain resistant to methicillin and the wild strain isolated from a hospital patient. Moreover, we asked whether eugenol could enhance the therapeutic effect of cefotaxime, one of the most prescribed 3rd generation cephalosporin β-lactam antibiotics, of which S. aureus resistance to this antibiotic has emerged. The minimum inhibitory concentration (MIC) of each substance was determined using the standard broth microdilution test following the combination experiment performed using checkerboard dilution. The type of interactions, including synergistic and additivity, was determined using isobologram analysis, and the dose reduction index (DRI) was calculated. The time-kill kinetic assay was performed to evaluate the dynamic bactericidal activity of eugenol alone and in combination with cefotaxime. We showed that eugenol alone is bactericidal against S. aureus ATCC 33591 and the clinical isolate. Eugenol combined with cefotaxime resulted synergistic effect against S. aureus ATCC 33591, ATCC 29213, and ATCC 25923. Eugenol may be capable to improve the therapeutic effect of cefotaxime against methicillin-resistant S. aureus (MRSA).

Hotspots sequences of gyrA, gyrB, parC, and parE genes encoded for fluoroquinolones resistance from local Salmonella Typhi strains in Jakarta

Background

Infection of Salmonella enterica subsp. enterica serovar Typhi is the primary etiology of typhoid fever globally and is common in many developing countries, especially those with dense populations and poor environmental sanitation. Antibiotic fluoroquinolones were used for the treatment in the 1980s due to the resistance to the first-line antibiotics. However, many cases of treatment failure of fluoroquinolones in typhoidal patients have been reported from numerous countries in Asia, Europe, Africa, and America. Mutations in quinolone resistance determining regions (QRDR) genes, gyrA, gyrB, parC, and parE, are found in fluoroquinolone-resistant Salmonella Typhi. Contrast reports came from the S. Typhi isolates in Indonesia, mainly Jakarta and the surroundings, obtained from patients with typhoid fever, with good sensitivity to the fluoroquinolones, i.e., nalidixic acid, ciprofloxacin, moxifloxacin, and levofloxacin. The present study, therefore, aimed to identify the hotspot sequences of gyrA, gyrB, parC, and parE genes of the local S. Typhi strains based on their susceptibility to fluoroquinolones from patients with typhoid fever in Jakarta and its satellite cities.

Results

A total of 28 isolates were identified as S. Typhi. All isolates were susceptible to nalidixic acid, levofloxacin, and moxifloxacin. Twenty-seven isolates (96.4%) were susceptible to ciprofloxacin, with one isolate (3.6%) being intermediate. The hotspot sequences of gyrA, gyrB, parC, and parE genes from all isolates were identical to the fluoroquinolone-sensitive reference sequence Salmonella enterica subsp. enterica serovar Typhi Ty2 (NCBI GenBank AE014613.1), including the isolate with intermediate susceptibility. The mutation was not found, and amino acid deduced from all hotspots in susceptible and intermediate isolates showed no replacement in all reported codons.

Conclusions

This study showed that the local S. Typhi strains from Jakarta and surroundings were susceptible to fluoroquinolones (nalidixic acid, ciprofloxacin, levofloxacin, and moxifloxacin), and the hotspot sequences of the gyrA, gyrB, parC, and parE genes were all identical to the reference sequence. Thus, the hotspot sequences of the gyrA, gyrB, parC, and parE genes seemingly were conserved in Jakarta’s local S. Typhi strains and could be considered wild type. The phenotypic susceptibility was consistent with the genotypic characteristic without non-synonymous mutations associated with drug resistance.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-022-02666-z.

Identification of Mycoplasma pneumoniae-associated pneumonia cases among hospitalized patients using CLART® microarray technology

Objectives

Community-acquired pneumonia (CAP) is a global health condition that affects populations from all age groups. The laboratory identification of Mycoplasma pneumoniae as a causative agent of CAP is challenging because of its atypical and fastidious nature. Therefore, this study assessed the diagnostic potential of PneumoCLART bacteria® in identifying M. pneumoniae as a causative agent of pneumonia in hospitalized adults.

Methods

This prospective study used a cross-sectional approach to assess the diagnostic potential of PneumoCLART bacteria® for detecting M. pneumoniae in sputum samples procured from 27 patients with pneumonia who required hospitalization.

Results

The PneumoCLART bacteria® results illustrated that 7 of 27 patients with pneumonia were positive for M. pneumoniae (26%). However, the quality of sputum varied among the M. pneumoniae-positive and M. pneumoniae-negative samples. Fifty percent of the specimens obtained from patients positive for M. pneumoniae were saliva-contaminated and unsuitable for analysis.

Conclusions

Because the leukocyte count was low and sputum specimens were saliva-contaminated, these findings require further validation to prove the utility of CLART® microarray technology for the identification of M. pneumoniae in pneumonia-positive patients. Conclusively, this prospective study included a small number of clinical samples, which likely affected its outcomes.

Distribution of Carbapenemase Genes among Carbapenem-Non-Susceptible Acinetobacter baumanii Blood Isolates in Indonesia: A Multicenter Study

Carbapenem non-susceptible Acinetobacter baumannii (CNSAB) is an important pathogen that causes nosocomial bacteremia among critically ill patients worldwide. The magnitude of antibiotic resistance of A. baumanii in Indonesia is expected to be significant; however, the data available are limited. The aim of this study was to analyze the genetic profiles of CNSAB isolates from patients with bacteremia in Indonesia. CNSAB isolates from blood cultures of bacteremia patients in 12 hospitals in Indonesia were included. The blood cultures were conducted using the BacT/Alert or BACTEC automated system. The CNSAB were identified with either Vitek 2 system or Phoenix platform followed by a confirmation test using a multiplex polymerase chain reaction (PCR) assay, targeting the specific gyrB gene. The carbapenemase genes were detected by multiplex PCR. In total, 110 CNSAB isolates were collected and were mostly resistant to nearly all antibiotic classes. The majority of CNSAB isolates were susceptible to tigecycline and trimethoprim-sulfamethoxazole (TMP-SMX), 45.5% and 38.2%, respectively. The bla_OXA-51-like gene was identified in all CNSAB isolates. Out of the total, 83.6% of CNSAB isolates had bla_OXA-23-like gene, 37.3% bla_OXA-24-like gene, 4.5% bla_NDM-1 gene, 0.9% bla_IMP-1 gene, and 0.9% bla_VIM gene. No bla_OXA-48-like gene was identified. The bla_OXA-23-like gene was the predominant gene in all except two hospitals. The presence of the bla_OXA-24-like gene was associated with resistance to tigecycline, amikacin, TMP-SMX and cefoperazone-sulbactam, while bla_OXA-23-like gene was associated with resistance to TMP-SMX and cefoperazone-sulbactam. In conclusion, the bla_OXA-23-like gene was the predominant gene among CNSAB isolates throughout Indonesia. A continuous national surveillance system needs to be established to further monitor the genetic profiles of CNSAB in Indonesia.

Diagnostic parameters of the AF Genital System® for detection of Mycoplasma hominis and Ureaplasma urealyticum

OBJECTIVE

The prevalence of Mycoplasma hominis and Ureaplasma urealyticum (genital mycoplasma) amongst Indonesian women is poorly understood because of limited availability of diagnostic techniques. We sought to compare the diagnostic parameters of the AF Genital System® with those of culture methods and PCR as the gold standard for identification of M. hominis and U. urealyticum in vaginal swab specimens.

METHODS

This was an observational diagnostic study. Eighty-eight specimens were collected from patients with abnormal vaginal discharge. Detection of M. hominis and U. urealyticum was performed using the AF Genital System®, culture methods, and PCR.

RESULTS

Compared with PCR and culture methods, respectively, the AF Genital System® had sensitivities of 66.6% and 57% (M. hominis) and 55.5% and 77.8% (U. urealyticum). Compared with PCR and culture methods, respectively, the AF Genital System® had specificities of 82.9% and 86.5% (M. hominis) and 82.3% and 84.8% (U. urealyticum).

CONCLUSION

The sensitivity of the AF Genital System® for detection of M. hominis and U. urealyticum from vaginal swab samples was lower than that of PCR, but specificity was reasonably good (82% to 83%).

Wide Application of Minimally Processed Saliva on Multiple RT-qPCR Kits for SARS-CoV-2 Detection in Indonesia

Saliva as a sample matrix has been an attractive alternative for the detection of SARS-CoV-2. However, due to potential variability in collection and processing steps, evaluating a proposed workflow amongst the local population is recommended. Here, we aim to validate the collection and treatment of human saliva as a direct specimen for RT-qPCR-based detection of SARS-CoV-2 in Indonesia. We demonstrated that SARS-CoV-2 target genes were detected in saliva specimens and remained stable for five days either refrigerated or stored at room temperature. The method of processing saliva specimens described in this report bypasses the need for an RNA-extraction process, thereby reducing the cost, time, and manpower required for processing samples. The developed method was tested across nine commercial kits, including the benchmark, to demonstrate its wide applicability on multiple existing workflows. Our developed method achieved an 86% overall agreement rate compared to paired nasopharyngeal and oropharyngeal swab specimens (NPOP). With the assistance of a saliva sampling device, the collection was found to be more convenient for individuals and improved the overall agreement rate to 97%.

Performance of TDR-300B and VITEK®2 for the identification of Pseudomonas aeruginosa in comparison with VITEK®-MS

Objective

Automated systems are needed for the rapid and accurate diagnosis of Pseudomonas-associated nosocomial infections among critically ill patients admitted to the intensive care unit. We assessed the performance of TDR-300B and VITEK®2 for the identification of P. aeruginosa using VITEK®-MS as the gold standard.

Methods

This analytical study employed a cross-sectional approach. First, 44 clinical isolates of P. aeruginosa were collected and refreshed. Next, a single colony of oxidase-positive, gram-negative rods (30 samples) was inoculated into a TDR-300B NF-64 card and VITEK®2 GN cassette for each isolate. Finally, bacterial identification was performed using VITEK®-MS for comparative analysis.

Results

Compared with the results for VITEK®-MS, the congruence rates for TDR-300B and VITEK®2 were 80.76% (21/26) and 92.30% (24/26), respectively. Further, high sensitivity was observed for TDR-300B and VITEK®2 (95.45% and 100%, respectively). In addition, TDR-300B had a lower positive predictive value and accuracy than VITEK®2, albeit without significance.

Conclusions

Conclusively, there were no significant differences regarding the diagnostic efficiency of TDR-300B and VITEK®2 for P. aeruginosa.

Comparison of BCYE and BMPA media on recovery rate of Legionella pneumophila

Latar belakang: Legionella pneumophila (L. pneumophila) telah banyak diketahui sebagai penyebab legionellosis; habitat nya di berbagai sumber air, lingkungan lembab dan hangat. Metode kultur menggunakan media spesifik masih menjadi baku emas untuk identifikasi L. pneumophila. Penelitian ini bertujuan membandingkan recovery rate L. pneumophila ATCC®33823 pada medium spesifik BCYE, dan medium selektif BMPA. Metode: Dilakukan dilusi serial pada suspensi 0,5 McFarland L. pneumophila ATCC®33823; 100 ul dari tiap tingkat dilusi diinokulasi pada medium Buffered Charcoal Yeast Extract (BCYE) dan medium BMPA (medium BCYE yang ditambahkan suplemen BMPA-α), secara duplo. Konsentrasi suspensi dihitung menggunakan metode Angka Lempeng Total (ALT) dari Standar Nasional Indonesia No. 01-2332.3-2006. Persentase recovery rate dihitung dan dianalisis secara statistik menggunakan SPSS versi 23,0. Hasil: Jumlah koloni L. pneumophila yang tumbuh pada medium BMPA jauh lebih tinggi daripada yang tumbuh di medium BCYE; konsentrasi tertinggi yang diperoleh adalah pada medium BMPA sebesar 1,45 x 107 CFU/ml. Persentase recovery rate pada medium BMPA adalah 96,67%, dan 60,67% pada medium BCYE. Kesimpulan: Recovery rate medium BMPA untuk pertumbuhan koloni L. pneumophila ATCC®33823 jauh lebih tinggi daripada media BCYE, karena itu medium BMPA dapat direkomendasikan untuk kultivasi L. pneumophila, khususnya pada program surveilans berbagai sumber air dengan biaya lebih terjangkau. Kata kunci: Legionella pneumophila, medium spesifik, BCYE , BMPA, recovery rate   Abstract Background: Legionella pneumophila (L. pneumophila) has been known as the etiology of legionellosis; they live in aquatic environment, warm and moist. Culture method using specific medium remains as the gold standard in the identification of L. pneumophila. This study aimed to compare the recovery rate of L. pneumophila ATCC® 33823 on the specific medium BCYE for the cultivation of Legionella, and BMPA, the selective medium. Methods: Suspension of L. pneumophila ATCC® 33823 of 0.5 McFarland was diluted to 10 fold serial dilution; 100 ul of each dilution was inoculated on Buffered Charcoal Yeast Extract (BCYE) medium, and BMPA (BCYE supplemented with BMPA-α) in duplicate manner. The concentration was calculated using Total Plate Count standard as of Indonesian Nasional Standard number 01-2332.3-2006. The percentage of recovery rate was calculated, and the statistical analysis was performed using SPSS version 23.0.   Results: Numbers of colonies of L. pneumophila grew on BMPA was much higher than on BCYE medium; the highest concentration was yielded on BMPA medium i.e. 1.45x107 CFU/ml. The recovery rates were 96.67% and 60.67% on BMPA medium and BCYE subsequently. Conclusion: The recovery rate of the BMPA medium on the colony growth of L. pneumophila ATCC®33823 was markedly higher than the BCYE, therefore BMPA medium can be suggested to be used in the cultivation of L. pneumophila especially in the routine surveillance program for water sources with less cost. Keywords: Legionella pneumophila, specific medium, BCYE , BMPA, recovery rate

Screening of Legionella pneumophila from water sources in the hospitals in Jakarta

Latar belakang: Pneumonia akibat bakteri Legionella masih menjadi masalah di berbagai tempat di dunia; menjadi penyebab 2-15 % dari pneumonia yang perlu di rawat di Rumah Sakit. Kasus legionellosis di Indonesia dilaporkan terjadi di Bali pada tahun 1996 dan di Tangerang tahun 1999. Keberadaan Legionella di fasilitas Pelayanan Kesehatan berpotensi sebagai penyebab infeksi nosokomial. Bakteri Legionella hidup di lingkungan perairan hangat dan lembab, juga ditemukan diberbagai sumber air seperti, sumber air sistem pendingin ruangan, kolam renang, tempat penampungan air di rumah sakit, perkantoran, hotel, dan perumahan sehingga turut berkontribusi dalam terjadinya community acquired dan pneumonia nosokomial. Metode: Penelitian ini merupakan penelitian deskriptif yang bertujuan untuk penapisan keberadaan Legionella pneumophila diberbagai sumber dan penampungan air di Rumah Sakit (RS) di Jakarta dengan menggunakan medium Legionella Charcoal Yeast Extract (CYE) dan dengan berbagai suplemen. Tujuh belas sampel air yang berasal dari berbagai sumber air di dua RS yang berlokasi diJakarta Utara dan Barat telah diteliti. Hasil: Dua puluh satu koloni yang ditemukan memiliki karakterisitik L. pneumophila dari semua varian medium, namun pada tes agglutinasi latex tidak memberikan reaksi positif. Kesimpulan: L. pneumophila tidak ditemukan diberbagai sumber air dari dua RS ini. Penggunaan metode yang lebih sensitif dan spesifik perlu dilakukan untuk memastikan ditemukannya L. pneumophila.  Kata kunci: Legionellosis, Legionella pneumophila, medium BCYE   Abstract Background: Pneumonia due to Legionella bacteria is still a problem in various places in the world, causes 2 15% of pneumonia that need hospitalization. In Indonesia, legionellosis cases have been reported in Bali in 1996 and Tangerang in 1999. The existence of Legionella in healthcare facilities is potential to cause nosocomial infections. Legionella bacteria live in warm and humid waters, and are also commonly found in various water sources, such as water cooling systems, swimming pools, water reservoirs in hospitals, offices, hotels and housing. These bacteria contribute to the occurrence of community-acquired and nosocomial pneumonia. Methods: This study was a descriptive research, and aimed to screen water sources and reservoirs in the hospitals in Jakarta for the existence of Legionella pneumophilla using Legionella Charcoal Yeast Extract (CYE) medium with various supplements. A total of 17 water samples from 2 hospitals located in West and North Jakarta have been examined. Results: The results showed a total of 21 colonies with characteristics as of L. pneumophila were obtained from those water samples, however, none showed positive results in the latex agglutination test. Conclusion: L. pneumophila was not found thus far in the water sources in these two hospitals. A more sensitive and specific approaches might be used to enable the findings of L. pneumophila.  Keywords: Legionellosis, Legionella pneumophila, BCYE medium

Trends in antimicrobial susceptibility of gram-negative bacteria isolated from blood in Jakarta from 2002 to 2008

BACKGROUND

This study examined the susceptibility of Gram-negative bacteria in the bloodstream to antimicrobials with the aim of providing information relevant to the guidance of therapy.

METHODOLOGY

Blood specimens received by the Laboratory of Clinical Microbiology, Faculty of Medicine, University of Indonesia, from 2002 to 2008, were analyzed for the presence of Gram-negative bacteria and their susceptibility to four antibiotic groups frequently administered in hospitals and community settings.

RESULTS

During the seven-year period leading up to 2008, approximately 68% of Gram-negative bacteria were identified among all positive isolates from blood specimens. The eight most frequent species found were Acinetobacter anitratus (25.8%), Pseudomonas aeruginosa (19.5%), Klebsiella pneumoniae subsp. pneumoniae (14.5%), Enterobacter aerogenes (8%), Salmonella Typhi (7.5%), Escherichia coli (6.2%), Alcaligenes faecalis (5.6%) and Klebsiella oxytoca (3.2%). At 80% susceptibility or greater, Ceftriaxone and Cefotaxime were active only on E. coli and S. Typhi. Cefepime demonstrated activity on all eight species tested except K. pneumonia while Amikacin showed activity against five species, A. faecalis, E. aerogenes, E. coli, K. pneumoniae subsp. pneumoniae and S. Typhi. Gentamycin was active against three species: E. aerogenes, K. oxytoca and S. Typhi. Ciprofloxacin and Levofloxacin significantly differed in their spectrum: while Ciprofloxacin was active against four of the eight species tested (E. aerogenes, E. coli, K. oxytoca, and S. Typhi ), Levofloxacin was similar to Cefepime and was active against all eight species except K. pneumoniae subsp. pneumonia.

CONCLUSIONS

Since antimicrobials are broadly used in Jakarta, it is important that the information captured in this study be disseminated.