Isolation of nontuberculous mycobacteria species from different water sources: a study of six hospitals in Tehran, Iran.

PURPOSE: Nontuberculous mycobacteria (NTM) are ubiquitous bacteria that are naturally resistant to disinfectants and antibiotics and can colonize systems for supplying drinking water. Therefore, this study aimed to evaluate the prevalence of NTM in the drinking water of six hospitals in Tehran, Iran. METHODS: Totally, 198 water samples were collected. Each water sample was filtered via a membrane filter with a pore size of 0.45 µm and then decontaminated by 0.005% cetylpyridinium chloride. The membrane filters were incubated on two Lowenstein-Jensen media at 25 °C and 37 °C for 8 weeks. The positive cultures were identified with phenotypic tests, and then NTM species were detected according to the hsp65, rpoB, and 16S rDNA genes. Drug susceptibility testing (DST) was also carried out. RESULTS: Overall, 76 (40.4%) of the isolates were slowly growing mycobacteria (SGM) and 112 (59.6%) of the ones were rapidly growing mycobacteria (RGM). The most common NTM were Mycobacterium aurum, M. gordonae, M. phocaicum, M. mucogenicum, M. kansasii, M. simiae, M. gadium, M. lentiflavum, M. fortuitum, and M. porcinum. Among these 188 samples, NTM ranged from 1 to > 300 colony-forming unit (CFU) /500 mL, with a median of 182 CFU/500 mL. In the infectious department of all hospitals, the amount of CFU was higher than in other parts of the hospitals. The DST findings in this study indicated the diversity of resistance to different drugs. Among RGM, M. mucogenicum was the most susceptible isolate; however, M. fortuitum showed a different resistance pattern. Also, among SGM isolates, M. kansasii and M. simiae, the diversity of DST indicated. CONCLUSIONS: The current study showed NTM strains could be an important component of hospital water supplies and a possible source of nosocomial infections according to the CFU reported in this study. The obtained findings also help clarify the dynamics of NTM variety and distribution in the water systems of hospitals in the research area.

Investigation into antibacterial and wound healing properties of platelets lysate against Acinetobacter baumannii and Klebsiella pneumoniae burn wound infections.

BACKGROUND AND AIM: Treatment of burn wound infections has become a global challenge due to the spread of multidrug-resistant bacteria; therefore, the development of new treatment options for the mentioned infections is essential. Platelets have drawn much attention for this purpose because they are a safe and cost-effective source of different antimicrobial peptides and growth factors. The present study evaluated antibacterial effects and wound healing properties of Platelet-derived Biomaterial (PdB) against Acinetobacter baumannii and Klebsiella pneumoniae burn wound infections. METHODS: PdB was prepared through the freezing and thawing process and then, in vitro antibacterial effect was determined by disk diffusion and broth microdilution methods. Afterward, burn wound was inflicted on 56 rats, infected with both bacteria, and topical administration was performed to evaluate antibacterial effects and wound healing properties of PdB. RESULTS: In vitro results showed that PdB inhibited the growth of A. baumannii in the highest dose (0.5), while we did not detect any inhibitory effects against K. pneumoniae. By contrast, PdB significantly inhibited the growth of bacteria in treated animal wounds compared to the control groups (P value < 0.05). Macroscopic assessments pointed to the significant enhancement of wound closure in the treated animals. In addition, histopathological examination demonstrated that treatment of rats with PdB led to a considerable increase in re-epithelialization and attenuated the formation of granulation tissue (P value < 0.05). CONCLUSION: The use of topical PdB is an attractive strategy for treating A. baumannii and K. pneumoniae burn wound infections because it inhibits bacterial growth and promotes wound healing properties.

Mycobacterium avium paratuberculosis and Mycobacterium avium complex and related subspecies as causative agents of zoonotic and occupational diseases.

Mycobacterium avium complex (MAC) and Mycobacterium avium paratuberculosis (MAP) cause zoonotic infections transmitted by birds and livestock herds. These pathogens have remained as serious economic and health threats in most areas of the world. As zoonotic diseases, the risk of development of occupational disease and even death outcome necessitate implementation of control strategies to prevent its spread. Zoonotic MAP infections include Crohn's disease, inflammatory bowel disease, ulcerative colitis, sarcoidosis, diabetes mellitus, and immune-related diseases (such as Hashimoto's thyroiditis). Paratuberculosis has classified as type B epidemic zoonotic disease according to world health organization which is transmitted to human through consumption of dairy and meat products. In addition, MAC causes pulmonary manifestations and lymphadenitis in normal hosts and human immunodeficiency virus (HIV) progression (by serotypes 1, 4, and 8). Furthermore, other subspecies have caused respiratory abscesses, neck lymph nodes, and disseminated osteomyelitis in children and ulcers. However, the data over the occupational relatedness of these subspecies is rare. These agents can cause occupational infections in susceptible herd breeders. Several molecular methods have been recognized as proper strategies for tracking the infection. In this study, some zoonotic aspects, worldwide prevalence and control strategies regarding infections due to MAP and MAC and related subspecies has been reviewed.

Inhibition of bacterial adhesion and anti-biofilm effects of Bacillus cereus and Serratia nematodiphila biosurfactants against Staphylococcus aureus and Pseudomonas aeruginosa.

Background and Objectives: Biosurfactants are amphiphilic surface-active agents that mainly produced by various microorganisms. In this study, the anti-biofilm and inhibition of bacterial adhesion activities of two bacterial biosurfactants were investigated. Materials and Methods: After extraction and evaluation of Bacillus cereus and Serratia nematodiphila biosurfctants, inhibition of bacterial adhesion and anti-biofilm effects of them on Staphylococcus aureus and Pseudomonas aeruginosa were determined. Results: On average, the synergistic effect of two bacterial biosurfactants, caused about 60% decrease in adhesion and about 80% decrease in biofilm formation of S. aureus and P. aeruginosa. Conclusion: The results of this study showed that combination of B. cereus and S. nematodiphila biosurfactants would increase the potential of attachment inhibition and biofilm eradication with very low toxicity.

Smaller Copper Oxide Nanoparticles have More Biological Effects Versus Breast Cancer and Nosocomial Infections Bacteria.

BACKGROUND AND OBJECTIVES: Despite promising successes in developing new drugs and pharmaceutical biotechnology, infectious diseases and cancer are still the principal causes of mortality and morbidity globally. Therefore, finding effective ways to deal with these pathogens and cancers is critical. Metal nanoparticles are one of the new strategies to combat bacteria and cancers. METHODS: We examined the antimicrobial activity of 30 and 60 nm copper oxide nanoparticles (CuO-NPs) against Acinetobacter baumannii and Staphylococcus epidermidis bacteria responsible for nosocomial infections in standard and clinical strains and anti-cancer activity against 4T1 cell line as malignancy breast cancer cells. Synthesis of CuO-NPs was performed by a one-step reduction method and confirmed by DLS and TEM microscopy at 30 and 60 nm sizes. The antibacterial and anti-cancer activities of the nanoparticles were then investigated against the aforementioned bacteria and breast cancer. RESULTS: Using disk, well, MIC, MBC methods, and viability/bacterial growth assay, 30 nm CuO NPs were found to have more antibacterial activity on standard and clinical strains than 60 nm CuO NPs. On the other hand, using MTT, apoptosis, and gene expression method, 30 nm nanoparticles were found to have more anti-cancer potential than 60 nm CuO NPs. CONCLUSIONS: Our findings implicate CuO-NPs to possess antimicrobial and anti-cancer effects and more significant potential in smaller sizes, suggesting their pharmaceutical and biomedical capacity.
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The effect of Bacillus coagulans on cytotoxicity and apoptosis induced by Salmonella Typhimurium in HT-29 cell culture.

BACKGROUND AND OBJECTIVES: Human epithelial cells have been widely used to study the interaction between intestinal cells and pathogens, in vitro. In this study, the effect of probiotic bacteria Bacillus coagulans and its supernatant on the growth inhibition, cytotoxicity and induction of apoptosis caused by Salmonella Typhimurium and its adhesion to HT-29 cells were investigated. MATERIALS AND METHODS: B. coagulans supernatant was used to obtain the minimum inhibitory concentration. To evaluate the cytotoxicity and percent of apoptotic cells, B. coagulans and its supernatant (2, 4, 6 and 8% concentrations) with S. Typhimurium was added to HT-29 cells. The MTT assay was used in order to evaluate the cytotoxicity. Percent of apoptotic cells was reported using a fluorescence staining method. Additionally, the adhesion of S. Typhimurium to HT-29 cells was investigated. The effect of B. coagulans on the level of adhesion was also studied. RESULTS: The most inhibitory effect was shown at the concentration of 80000 µg/ml supernatant of B. coagulans (54.77% ± 1.43). The simultaneous culture of S. Typhimurium with B. coagulans had the lowest amount of cytotoxicity and induced apoptosis among the all co-culture groups of S. Typhimurium with B. coagulans or its supernatant. The determined cytotoxicity and induced apoptosis were 26.06 % ± 3.79 and 17.63 % ± 2.14 respectively. In the adhesion test, it was observed that B. coagulans can significantly prevent adhesion of S. Typhimurium to HT-29 cell. CONCLUSION: B. coagulans can reduce the adhesion, cytotoxicity and induction of apoptosis caused by S. Typhimurium in HT-29 cells in vitro.

Virulence determinants and biofilm formation of Acinetobacter baumannii isolated from hospitalized patients.

INTRODUCTION: Acinetobacter baumannii are nosocomial bacteria that are responsible for outbreaks and severe infections in hospitalized patients globally. The major target of this study was the characterization of virulence determinants and biofilm formation of A. baumannii isolates from hospitalized patients. METHODS: In total, 100 A. baumannii were collected from three hospitals in Tehran, Iran, 2017-2018. The isolates were assessed using phenotypic and genotypic methods and then screened for virulence factor encoding genes such as plcN and lasB using conventional polymerase chain reaction. Furthermore, bacterial biofilm formation, motility and hemolytic and proteolytic activities were assessed. RESULTS: Of 100 A. baumannii isolates, 20 isolates included plcN and four isolates included lasB using PCR assay. Overall, 21 isolates were negative for biofilm formation while 45, 20 and 14 of the total isolates were reported as weak, moderate and strong biofilm producers, respectively. All isolates were positive for bap genes using PCR. Moreover, 35 isolates were motile on Luria-Bertani media, 47 isolates were α-hemolytic on Brucella blood agar media and all isolates displayed proteolytic activity. CONCLUSIONS: Healthcare-associated infections with A. baumannii are a major concern, importantly due to their potency to acquire virulence factor genes. Therefore, shedding light in the discovery of new antimicrobial and/or therapeutic agents against virulent A. baumannii strains seem to be necessary.

Prevalence of Clinically Isolated Metallo-beta-lactamase-producing Pseudomonas aeruginosa, Coding Genes, and Possible Risk Factors in Iran.

BACKGROUND & OBJECTIVE: The spread of carbapenem-resistant Pseudomonas aeruginosa is a global concern. Metallo-beta-lactamase (MBL) enzymes cause extensive drug resistance among Gram-negative bacteria. The current study aimed at determining the prevalence of MBL-producing P. aeruginosa in Iran. DATA EXTRACTION: A total of 43 studies were found out of which 36 were adopted. Data were collected from Google, Google Scholar, Science Direct, PubMed, Scopus, Embase, and Sciverse. The terms "Pseudomonasaeruginosa", "metallo-beta-lactamase", "prevalence", "carbapenems", and "Iran" were searched. Data from the isolates not producing MBLs were excluded from the study. Data were analyzed with Graph Pad Prism 6, meta-analysis section. RESULTS: According to the results of the current study, 36 surveys indicated that 55% of the clinically isolated P. aeruginosa in Iran were resistant to imipenem and meropenem, among which 37.72% were the MBL producers. Among genes encoding MBLs, blaVIM and blaIMP were predominant with the prevalence of 12.91%±11.01% and 12.50%±23.56%, respectively. No report of harboring blaNDM1 and blaSPM1 by P. aeruginosa was found, similar to most of the other countries in Asia. The prevalence of blaVIM and blaIMP from burn settings were 11.50%±3.5% and 24.65%±23%, respectively. Furthermore, the prevalence of these genes was not significantly different among burn and non-burn isolates (P=0.942 and P=0.597, respectively). Moreover, no relationship was observed between the MBL production and patients' age range. CONCLUSION: Approximately half of P. aeruginosa isolates were carbapenem-resistant in Iran, and approximately half were the MBL producers. The blaVIM and blaIMP were the predominant MBLs among P. aeruginosa strains, while other genes were not found in P. aeruginosa. Moreover, there was no significant difference between blaVIM and blaIMP among burn and non-burn isolates. Due to the multiple drug resistance conferred by MBLs, detection and control of their spread alongside proper therapeutic regimens in hospitals and community settings are essential to prevent infection acquisition.