Journal of Medical Bacteriology

Detection of Efflux Activity in Macrolide Resistant Streptococcus pyogenes Obtained from Patients with Throat Infections

2025-05-05T19:01:24+0430

Background: Streptococcus pyogenes are bacteria which cause a wide variety of clinical manifestations including pharyngitis. Macrolides are alternative treatment options in cases of penicillin allergy or penicillin treatment failure. Due to a global rise in the emergence of macrolides resistance among these bacteria, the need for easy and rapid identification of isolates over-expressing efflux is paramount. This study detected the efflux-pump mediated resistance in macrolide resistant Streptococcus pyogenes using the ethidium-bromide (EtBr)–Agar cartwheel method.

Methods: Overnight cultures of Streptococcus pyogenes isolates obtained from patients with throat infection were prepared. Agar plates containing EtBr of different concentrations were prepared. The minimum inhibitory concentration (MIC) of carbonyl cyanide m-chlorophenylhydrazine (CCCP) was determined.

Results: The isolates identified as isolates 190 (Reference strain), 22, 78, and 114 (iMLSB phenotypes) fluoresced at a concentration of 1.0 mg/l of EtBr; isolate 101 did not fluoresce even at a concentration of EtBr as high as 2.0 mg/l. The effect of ½ MIC of CCCP on the MIC of Erythromycin was tested and in the presence of CCCP at a concentration of 4µg/ml, the MIC of erythromycin was decreased by 2 to 4-fold.

Conclusion: The ethidium bromide-agar cartwheel method provided an easy and instrument-free means by which rapid evaluation of antibiotic resistance through the use of efflux pumps in bacterial isolates can be conducted.

Comparative Analysis of Healthcare-Associated Infections in Gastroenterology and Gastro surgery: A Two-Year Retrospective Study at GB Pant Hospital, New Delhi

2025-05-05T19:01:25+0430

Background: Healthcare-associated infections (HAIs) pose significant challenges in gastroenterology and gastrosurgery. This study aimed to compare infection characteristics between these two patient populations at a tertiary care center in India, focusing on gastro-specific samples.

Methods: We conducted a retrospective observational study of 824 patients (412 each in gastroenterology and gastrosurgery) over 24 months at GB Pant Hospital, New Delhi. Infections were defined using CDC criteria. Microbiological identification and antimicrobial susceptibility testing were performed on gastro-specific samples. Risk factors were analyzed using multivariate logistic regression.

Results: Infection rates were significantly higher in gastrosurgery patients (18.4% vs. 7.5%, p<0.001). Escherichia coli was the predominant pathogen in both groups (gastroenterology: 30.6%, gastrosurgery: 28.9%). Antimicrobial resistance was more prevalent in gastrosurgery isolates, with 48.7% ESBL-producing Enterobacteriaceae compared to 27.3% in gastroenterology. Independent risk factors for infection differed between groups, with proton pump inhibitor use significant in gastroenterology (OR 2.3, 95% CI 1.5-3.5) and prolonged operative time in gastrosurgery (OR 2.8, 95% CI 1.9-4.2).

Conclusion: Significant differences in infection profiles between gastroenterology and gastrosurgery patients necessitate tailored prevention and treatment strategies.

Molecular and Histopathological Diagnosis of Bovine Viral Diarrhea Virus in a Dairy Cattle Farm Associated with an Abortion Storm

2025-05-05T19:01:25+0430

Background: Bovine viral diarrhea (BVD) which caused by a pestivirus, results in huge economic losses through abortion, weight loss, drop in milk production and even death of the affected animal. Reproductive disorders due to the virus infection are common in unvaccinated herds which are predominant causes of dairy cattle exclusion. The present study diagnosed BVD infection associated with an abortion storm in a farm following vaccination cessation. In addition, the present report investigated a variety of the disease complications other than abortion and it emphasized on the elimination of all the risk factors before any interruption in vaccination plan.

Methods: The specimens were collected from 66 aborted fetuses and examined by real-time RT-PCR and histopathological methods for the presence of BVD virus.

Results: Real-time RT-PCR detected BVDV in 47.14% of the aborted fetuses. The lesions of BVD were visible in the samples obtained from aborted fetuses.

Conclusion: In the studied herd, we could see several complications of BVD such as infertility, abortion and agalactia. Each of the disorder has significant economic losses on dairy cattle herds, so it is necessary to implement control programs such as biosecurity and monitoring before any decision to stop vaccination.

Virulence Genes Encoding for Panton Valentine Leucocidin and Toxic Shock Syndrome Toxin in Methicillin Resistant Staphylococcus aureus

2025-05-05T19:01:25+0430

Background: The outcome of Staphylococcal infections ranging from mild skin infection to fatal necrotising pneumonia is determined by the co-presence of virulence factors such as enzymes, toxins (Panton valentine leucocidin & toxic shock syndrome toxin) and methicillin resistance. In this study the association of toxin genes encoding for PVL and TSST was seen with drug resistance.

Methods: Staphylococcus aureus isolates collected from clinical samples (pus, tracheal aspirate, wound swabs and blood) from inpatients of the tertiary care hospital. The isolates were analysed for presence of toxin genes and drug resistance. DNA extraction was done by boiling method and target genes were identified by PCR and gel electrophoresis. The data was analysed using Microsoft excel. Chi-square test was used for comparison of qualitative data. Unpaired t test was used for comparison of quantitative data. P value less than 0.05 was taken as significant.

Results: Methicillin resistance was seen in 54.8% (108/197) of the staphylococcal isolates. There was no significant difference in MRSA and MSSA distribution amongst hospitalized or outpatients. The PVL and TSST gene was present in 123 (62.4%) and 29 (14.7%) isolates respectively. The presence of both the PVL and TSST were significantly higher in MRSA (P≤0.05).

Conclusion: There was significantly higher association of virulence markers such as PVL and TSST in MRSA. The presence of toxins should be investigated from cases of non-resolving MRSA infections to initiate treatment effective against toxins for patient management.

Prevalence and Molecular Typing of Non-Tuberculous Mycobacteria in Hospital Water Sources of Tehran, Iran

2025-05-05T19:01:25+0430

Background: Non-tuberculous mycobacteria (NTM) pose a growing public health concern, especially in regions with high prevalence rates. Iran, situated near high-burden countries like Afghanistan and Pakistan, is particularly vulnerable. This study aimed to investigate the molecular epidemiology of NTM in water samples from Farhikhtegan Hospital, Tehran.

Methods: A total of 70 water samples were collected from various hospital departments. After culture and phenotypic identification, 33 mycobacterial isolates were subjected to polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of the rpoB gene.

Results: Mycobacterium fortuitum type I was the most prevalent NTM species, accounting for 81% of the isolates. Mycobacterium kansasii type I and Mycobacterium gordonae type I followed, each comprising 6% of the isolates. Less common species included M. gordonae type II and Mycobacterium intracellulare. The PCR-RFLP method proved to be a sensitive and accurate tool for identifying NTM species.

Conclusion: This study provides valuable insights into the NTM profile in Farhikhtegan Hospital and underscores the importance of effective surveillance and control measures to mitigate the risk of NTM infections.

Brucella melitensis in Iranian Dairy Cattle: Isolation, Molecular Identification, and Biotyping

2025-05-06T09:15:09+0430

Background: Brucellosis, caused by Brucella species, remains a significant zoonotic and economic challenge in Iran, where Brucella melitensis is increasingly detected in dairy cattle due to close contact with infected sheep and goats. The persistence of B. melitensis highlights the limitations of existing control strategies and the need for improved approaches. Investigating B. melitensis in Iranian dairy cows is crucial due to their interaction with mixed sheep and goat populations.

Methods: In 2021, 73 lymphoid tissue samples were collected from reactor-positive cows in seven Iranian provinces. Samples were analyzed using traditional bacteriological methods, biotyping, and molecular tools such as AMOS-PCR and Bruce-ladder PCR for strain identification and characterization. Samples were collected from seven provinces in Iran, namely Tehran, Kerman, Isfahan, Alborz, Qazvin, West Azerbaijan, and Fars.

Results: Out of 73 lymph node samples collected from seven Iranian provinces, 15 (20.55%) tested positive for B. melitensis through culture and PCR. Culture results confirmed uniform growth conditions with no significant differences among provinces. Molecular analysis validated the identity of all isolates, with AMOS-PCR amplifying a 731 bp product and Bruce-ladder PCR confirming field strains through species-specific DNA fragments. Biotyping revealed that 14 isolates were B. melitensis Biotype 1, distributed across six provinces, while one isolate from Kerman Province was Biotype 3.

Conclusion: The prevalence of B. melitensis in Iranian dairy cattle highlights significant gaps in existing vaccination programs and the urgent need for cross-species protective vaccines. Given its zoonotic risks and public health impact, enhanced surveillance, advanced diagnostics, and region-specific strategies are critical for effective control.The RB51 vaccine has notable limitations, including its inability to protect against B. melitensis, lack of standardized protocols, and failure to aid in brucellosis eradication. Collaboration among public health authorities, veterinarians, and policymakers is critical to address these challenges and mitigate the spread of B. melitensis in Iran.

Ventilator-Associated Pneumonia in COVID-19 Patients: Prevalence and Associated Factors

2025-05-06T09:22:58+0430

Background: COVID 19 pandemic has resulted in increased ICU admission, with many patients requiring mechanical ventilation resulting in more incidences of ventilator associated pneumonia (VAP). Despite vast research on COVID 19 complications, very few studies have looked at the risk factors of VAP in this population. The purpose of this study is to bridge this gap by identifying clinical and laboratory predictors of VAP in critically ill COVID-19 patients.

Methods: Shahid Beheshti Hospital, Kashan was the site of a retrospective analysis of 235 COVID 19 ICU patients requiring mechanical ventilation. Therapeutic interventions were assessed and clinical symptoms, laboratory markers were assessed.

Results: Fever and chills were also found to be associated with nearly a threefold increase in risk (p < 0.05) as was abnormal heart rate, which increased the risk fourfold (p < 0.001), and WBC and ESR significantly correlated with VAP occurrence. In addition, patients not treated with tocilizumab had a sixfold increase in risk of VAP (p < 0.001). Early identification and targeted interventions to mitigate the risk of VAP in COVID-19 patients being mechanically ventilated is a focus of this study. Conclusion: Results indicate immunomodulatory therapy may provide a protective role, and underscore the importance of strict infection control. Future research should model causal mechanisms and develop best treatment strategies to reduce the incidence of VAP.

Comparison of the Diagnostic Accuracy of the Xpert MTB/RIF Assay with Acid-Fast Staining and Culture Methods for Prompt Detection of Mycobacterium tuberculosis Isolates

2025-05-06T09:32:56+0430

Background: The aim of this study was to compare the diagnostic accuracy of the GeneXpert with acid-fast stain (AFB) and culture methods in patients with suspected pulmonary tuberculosis (SPT).

Methods: A total of 484 sputum and BALF (bronchoalveolar lavage fluid). Samples were analyzed from 428 individuals, of which 78.3% were men and the average age was 49.9 years.

Results: The GeneXpert test had a sensitivity of 95.7% and a specificity of 43.9% for MTB culture, and a sensitivity of 91.9% and a specificity of 52.8% for a definitive diagnosis. The sample had a sensitivity of 93.7%, specificity of 69.6%, and accuracy of 82.2% for MTB culture, and sensitivity of 86.9%, specificity of 82.2%, and accuracy of 85.3% for the final diagnosis. Overall, the AFB exam had the highest diagnostic accuracy of the three tests at 85.3%.

Conclusion: The study indicates that while the study's AFB test is usually used as the first diagnostic test for pulmonary TB due to its high accuracy, the GeneXpert test can be used in samples that are AFB negative, but strongly suspected for TB, because it has a higher sensitivity. Choosing the appropriate test based on the clinical context is critical for accurate diagnosis and treatment of TB.

Investigating the Microbial Contamination of the Hands of Healthcare Staff and Medical Equipment in Different Wards of Hospital in Zahedan, Southeastern Iran

2025-05-06T09:44:25+0430

Background: Nosocomial infections are one of the serious problems in medical centres that can lead to the death of patients. Contamination of medical devices and surgical equipment is known as one of the main causes of the spread of these infections.

Methods: In this study, 442 medical and non-medical devices of Ali Ebne Abi Taleb Hospital in Zahedan) medical and non-medical devices that have more contact with the patient (were collected over two years and every month according to the schedule

Results: The most contamination was related to the hands and nails of the personnel, where 26 cases were positive with coagulase-negative Staphylococcus. Then, suction with Pseudomonas aeruginosa contamination was positive in 15 cases, followed by stethoscope and sialic lamp in the operating room, each of which were positive in 11 cases.

Staphylococcus was the most common organism in all departments and was isolated mostly from patients' beds, staff's hands and nails, and stethoscopes.

Conclusion: To reduce the level of contamination and prevent the spread of hospital infections, it is necessary to observe hygiene principles such as hand washing, regular disinfection of equipment, and use of standard guidelines to prevent infections.

Bacteroides fragilis-Associated Intra-Abdominal Abscess Following Penetrating Trauma

2025-05-06T16:15:33+0430

Background: Bacteroides fragilis is a clinically significant anaerobic bacterium known to cause abdominal infections, abscesses, sepsis, and skin and soft tissue infections. We report a case of an intra-abdominal wound infection following a penetrating injury, attributed to B. fragilis.

Methods: Foul-smelling pus from the abdominal wound was collected and sent for anaerobic culture using Robertson’s cooked meat medium. Gram staining and culture were performed on blood agar supplemented with haemin and vitamin K1. The sample's gram stain revealed gram-negative bacilli.

Results: Colony growth was observed on blood agar after 48 hours and was identified as B. fragilis through phenotypic biochemical tests, MALDI-TOF MS, and real-time PCR. The patient was successfully managed with metronidazole.

Conclusion: Prompt diagnosis and early treatment were crucial in reducing the morbidity and mortality associated with this infection.

Vaccination against Pathogenic Bacteria: An Insight into Polysaccharide and Conjugate Vaccines

2025-05-06T15:19:48+0430

Background: The cellular glycocalyx, a dense and complex coating of glycans, surrounds the surface of cells and serves as a critical interface between the cell and its external environment. Within this glycocalyx, the intricate glycans play essential roles in a variety of biological processes, including mediating cell-cell interactions, facilitating bacterial pathogenicity, and providing protection against environmental stressors such as desiccation, immune responses, and antimicrobial agents. The polysaccharides found on the outer surface of bacterial cells are particularly noteworthy due to their high degree of conservation across species and their easy accessibility. These characteristics make them excellent targets for immunological purposes, as they can be readily recognized by the immune system. As a result, bacterial polysaccharides and their repetitive units have been extensively studied and utilized as antigens in the development of vaccines with antibacterial properties. These vaccines leverage the unique structural features of polysaccharides to elicit robust and specific immune responses, offering a promising strategy for combating bacterial infections and enhancing public health.

Conclusion: In conclusion, it is important to emphasize that the topic explored in this article is vast, and the research field has experienced rapid growth in recent decades with ongoing advancements. Given the breadth of this field, it is challenging to cover the entire spectrum of polysaccharide-based bacterial vaccines targeting all bacterial pathogens. Additionally, due to inherent limitations, it was not feasible to include all research on polysaccharide and glycoconjugate vaccine development for a comprehensive set of bacterial pathogens. Therefore, only a subset of common bacteria and related vaccine development efforts have been evaluated in this discussion. Despite these limitations, the progress made in this area underscores the potential of polysaccharide-based vaccines as a powerful tool in the fight against bacterial infections.