Journal of Medical Microbiology and Infectious Diseases
Volume:11 Issue: 2, Spring 2023

The global COVID-19 pandemic has disproportionately impacted people with weakened immune systems. Non-communicable diseases, which include diabetes and cancer, are the top causes of weakened immune systems, recording up to 74% of all deaths globally. Studying the seroprevalence is crucial in understanding the epidemiology of the virus and contributes to the improved management of COVID-19 amongst patients with cancer and diabetes.

The study was a single-center prospective study that tested serum samples for routine chemical analysis from March to July 2022 at NHLS, Chemical Pathology, Polokwane laboratory using the COVID-19 IgG/IgM Rapid Test Cassette - Orient Gene Biotech, Zhejiang, China. The assay tests antibodies against SARS-CoV-2 in the early (lgM) and later stage (lgG) of infection.

Of the 207 patients with diabetes, 84% had detectable IgG and IgM antibodies against SARS-CoV-2. Similarly, 81% of the 283 cancer patients had detectable IgG and IgM antibodies against SARS-CoV-2. The patients with diabetes had a median age of 56 years (range: 0-91), and 60% were females. The cancer patients had a median age of 62 years (range: 49-72), and 40% were females.

The study demonstrates a high SARS-CoV-2 IgG and IgM antibody seroprevalence in diabetic and oncology patients at Pietersburg Hospital, Limpopo, South Africa. These findings emphasize the importance of ongoing serologic testing to track the pandemic, particularly among immunocompromised patients, and inform the development of effective public health strategies to mitigate COVID-19 transmission.

COVID-19, caused by the SARS-CoV-2 virus, had a widespread impact on lives worldwide. Its global impact has transcended geographical barriers, affecting people of all ages, races, and genders. Pregnancy induces critical physiological changes in women that can increase their susceptibility to infections. As a result, pregnant women may be at a higher risk of acquiring infections compared to non-pregnant individuals. This retrospective study aimed to determine the prevalence of COVID-19 among pregnant women from April 2020 to January 2022.

Screening was performed on a total of 4929 pregnant women nearing their expected delivery date. Nasopharyngeal and/or oropharyngeal samples were collected and analyzed for SARS-CoV-2 detection using real-time RT-PCR.

Pregnant women in the study had a mean age of 30.28 years, and the overall prevalence of COVID-19 was 3.6%. Positivity rates varied between zero and 23.2% during different intervals, with increases in positivity coinciding with the peaks of the country's first, second, and third waves of COVID-19. Pregnant females exhibited a higher positivity rate for COVID-19 compared to the general population.

The presence of COVID-19-positive patients in our study group, which comprised entirely of asymptomatic individuals, underscores the importance of active screening among at-risk populations, particularly during periods of increased activity in the general population. These findings can be of vital importance for the management of COVID-19 in pregnant patients, as well as policymaking at all levels.

Extra-pulmonary tuberculosis (EPTB) is a significant cause of morbidity, and early diagnosis is critical for improving patient outcomes. Conventional diagnostic methods for EPTB often require improvement, highlighting the need for more rapid and sensitive diagnostic procedures. In this cross-sectional study, we aimed to evaluate the diagnostic usefulness of multiplex PCR (mPCR) using IS6110 and mpb64 as gene targets for detecting Mycobacterium tuberculosis in samples from suspected cases of EPTB. We compared the performance of mPCR with conventional methods, including Ziehl Neelsen (ZN) microscopy, culture in LJ media, and BacT/Alert system. Our study aimed to provide insight into the utility of mPCR and its different targets for diagnosing EPTB in our setting.

We conducted a cross-sectional survey of 250 non-repeat clinical samples from extrapulmonary sites to detect M. tuberculosis. Both conventional diagnostic methods, including ZN microscopy, culture in LJ media, and BacT/Alert system, and molecular methods, including multiplex PCR (mPCR) using IS6110 and mpb64 as gene targets, were performed on the samples. Of the 250 samples, results for all the diagnostic methods were available for 116 samples, which were included in the final analysis. The study population comprised 83 patients with suspected EPTB and 33 controls.

Among the 83 samples in the EPTB group, conventional diagnostic methods, including ZN microscopy, LJ culture, and BacT/Alert system, showed low positivity rates of 6.02%, 8.43%, and 15.66%, respectively. In contrast, multiplex PCR (mPCR) using IS6110 and mpb64 as gene targets showed a significantly higher positivity rate of 79.51%. The IS6110 gene was amplified in 79.51% of the samples, while mpb64 was amplified in 49.39%.

Our study demonstrates that multiplex PCR (mPCR) using IS6110 and mpb64 as gene targets is a more sensitive diagnostic method for extra-pulmonary tuberculosis (EPTB) than conventional methods. Both IS6110 and mpb64 showed high sensitivity of 100%, but mpb64 was more specific when compared with the gold standard. Our findings suggest that mPCR, particularly with the inclusion of mpb64 as the target gene, may be a valuable tool for the early and accurate diagnosis of EPTB.

Acinetobacter baumannii is the cause of nosocomial infections, primarily in intensive care units. The pgaA gene plays an essential role in biofilm formation, making it a promising target for developing new strategies to tackle A. baumannii infections. This study investigated the meropenem effect on pgaA gene expression and biofilm formation in A. baumannii.

Over five months, 50 urine samples were taken from patients receiving medical care in the intensive care unit, of which 20 A. baumannii isolates were detected. Antibiotic susceptibility was determined with meropenem, imipenem, trimethoprim/sulfamethoxazole, ceftazidime, ciprofloxacin, tetracycline, amikacin, as well as gentamicin disks by the Kirby-Bauer method. The minimum inhibitory concentration (MIC) of meropenem was determined using the microdilution method. Biofilm formation was investigated through the tissue culture plate (TCP) technique and imaged using an atomic force microscope (AFM). Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) determined the expression level of the pgaA gene.

Antibiotic susceptibility testing revealed that all A. baumannii isolates were resistant to meropenem, imipenem, ciprofloxacin, and amikacin, and 71.42% were resistant to tetracycline. The MIC for meropenem could not be determined for isolates. Meropenem prevented biofilm formation in more than 70% of the isolates, and AFM imaging revealed thin biofilms. The RT-PCR showed that exposure to meropenem significantly decreased the pgaA expression gene in over 95% of the isolates (P < 0.0001).

Meropenem inhibited biofilm formation in most A. baumannii isolates by downregulating the pgaA expression, suggesting a potential role in preventing A. baumannii infections by reducing biofilm formation

According to global cancer statistics, oral cancer is the 11th most prevalent cancer worldwide. Despite the availability of numerous modern treatments for oral cancer, a complete reduction of mortality rates has not been achieved. Bacterial toxins have potential applications in inducing apoptosis or targeting tumor cells for destruction. The present study aimed to investigate the impact of Staphylococcus aureus seb and α-toxin genes on apoptotic-related gene mRNA expression, as well as apoptosis induction in KB cell lines, focusing on BAX, RB, BCL-2, and BAG-1 genes.

The transfection of KB cells was performed using Lipofectamine 2000 to introduce pcDNA3.1 (+)-seb, pcDNA3.1 (+)-α-toxin, or an empty pcDNA3.1 (+) plasmid. The cells were cultured in DMEM supplemented with 10% FBS and 800 mg/L of G418 to select cells containing the plasmids. Subsequently, real-time RT-PCR was performed to measure the mRNA expression levels of BAX, RB, BCL-2, and BAG-1 genes. Cell apoptosis was assessed using Annexin V/PI staining and flow cytometry.

The seb and α-toxin significantly alter the expression of apoptotic-related genes in the KB cell line. In transfected KB cells, there was a significant increase in the mRNA expression of BAX and RB genes and a substantial decrease in the mRNA expression of BCL-2 and BAG-1 compared to the control group. Annexin test and flow cytometry analysis revealed that seb was more effective than α-toxin in inducing apoptosis.

The seb and α-toxin genes of S. aureus exhibit an inhibitory effect on the growth, proliferation, and invasion of oral cancer cells by modulating gene expression in the apoptotic pathway. Hence, these toxins are promising for controlling and treating human oral cancer

Treating Gram-negative bacteria that produce extended-spectrum beta-lactamases (ESBLs), AmpC Beta lactamases, and carbapenemases is a significant clinical concern worldwide. To address this concern, Ceftazidime-Avibactam has been approved by the United States Food and Drug Administration (USFDA) as a practical option for combating multi-drug resistant (MDR) and extensively drug-resistant (XDR) organisms. Our study focused on determining the extent to which MDR Gram-negative organisms from various clinical samples exhibited resistance to CAZ-AVI.

Conducted at a central India tertiary care teaching hospital, our prospective study analyzed 258 Gram-negative bacteria specimens. These bacterial strains were identified using standard biochemical tests. ESBL production was detected using the combination disk method, while the AmpC enzyme was detected using the Epsilometer test (E-test). Furthermore, we assessed carbapenemase production using disk diffusion methods. Our study used the E-test to identify Metallo-beta-lactamases and Klebsiella pneumonia carbapenemase (KPC) activity. Additionally, we utilized the E-test to analyze the susceptibility patterns of CAZ-AVI.

Of the 258 Gram-negative isolates studied, 214 (83%) were ESBL producers. Among these isolates, 90 (35%) showed evidence of AmpC beta-lactamase production, with 17 (19%) being pure AmpC producers and 73 (81%) being ESBL co-producers. 55 (21.50%) were found to be carbapenemase producers. Among these isolates, 34 (62%) were MBL producers, while 11 (20%) were KPC producers. Of the carbapenemase-producing isolates, 14 (25.50%) were resistant to CAZ-AVI. Among the MDR isolates, we found that CI 109 (90%), PB 118 (97.50%), and FO 113 (93.50%) were the most effective antimicrobial agents.

Gram-negative organisms that produce ESBL, AmpC, Carbapenemase, MBL, and KPC are particularly challenging for clinicians and a significant threat worldwide. However, our study results suggest that CAZ-AVI could be an effective standard therapy for managing MDR Gram-negative organisms.

Lower respiratory tract infections (LRTIs) are a common global health problem, and antibiotic resistance remains a significant concern for doctors. This study aimed to determine the prevalence of antibiotic resistance among bacterial pathogens isolated from bronchoalveolar lavage (BAL) fluid at a tertiary care center in Western Uttar Pradesh.

A cross-sectional study was conducted from January 2021 to June 2022, in which BAL fluid samples were collected from patients attending the tertiary care center. The samples were processed for bacterial culture and antimicrobial susceptibility testing.

Out of 112 BAL samples cultured, 84 showed growths of bacterial pathogens, with 82 (97.6%) being Gram-negative bacteria and 29 (35%) of these being extended-spectrum beta-lactamase (ESBL) producers. The percentage of multiple drug-resistant (MDR) isolates was 77.38% (65/84). The Gram-negative isolates were most sensitive to imipenem, followed by ciprofloxacin, amikacin, and tetracycline. Cephalosporins and piperacillin-tazobactam showed a high resistance pattern to these bacteria. The Gram-positive isolates were susceptible to linezolid and vancomycin.

The high prevalence of ESBL-producing and MDR isolates in BAL samples highlights the need for the prudent administration of antibiotics and the creation of local antibiograms to guide empirical therapy. This study provides valuable information on the antimicrobial susceptibility patterns of bacterial pathogens causing LRTIs, which can aid in developing effective treatment strategies.

Pseudomonas aeruginosa, a Gram-negative bacterium, is the cause of infections in immunocompromised individuals, resulting in various conditions, including pneumonia, and urinary tract, skin, and bloodstream infections. This pathogen produces tissue-destructing toxins, leading to significant morbidity and mortality in affected patients. Conventional antibiotics, including rifampicin and colistin, are often ineffective in treating P. aeruginosa infections due to the emergence of bacterial resistance within affected communities. Alternatively, algae have been explored as a promising source for controlling pathogenic bacteria. In this study, we investigated the antibacterial effects of ethanol and aqueous extracts of Spirulina platensis against P. aeruginosa.

Ethanol and aqueous extracts of S. platensis were prepared at concentrations of 0.125, 0.25, 0.5, and 1 mg/mL. The antibacterial effect of Spirulina blue-green algae against P. aeruginosa was conducted using a disc diffusion test in an LB medium with 7-mm wells. We measured the inhibition zone and statistically analyzed the data by comparing the means using the Duncan multiple range test.

The ethanol extract of S. platensis significantly inhibited the growth of P. aeruginosa. Furthermore, applying the ethanol extract of S. platensis at a concentration of 1 mg/mL resulted in the largest inhibition zone (20 mm) compared to the control. In contrast, the S. platensis aqueous extract did not significantly inhibit P. aeruginosa growth.

The ethanol extracts of S. platensis algae exhibited a significant antibacterial effect against P. aeruginosa. This alga represents a promising source of antibacterial metabolites, which could be a suitable alternative to common antibiotics. Further investigations are necessary to identify and purify the specific antibacterial substance in S. platensis.