Species diversity and molecular analysis of opportunistic Mycobacterium, Nocardia and Rhodococcus isolated from the hospital environment in a developing country, a potential resources for nosocomial infection

Pathogenic bacteria and fungi in bioaerosols from specialized hospitals in Shandong province, East China

Bacteria and fungi are abundant and ubiquitous in bioaerosols in hospital environments. Understanding the distribution and diversity of microbial communities within bioaerosols is critical for mitigating their detrimental effects. Our knowledge on the composition of bacteria or fungi in bioaerosols is limited, especially the potential pathogens present in fine particulate matter (PM2.5) from specialized hospitals. Thirty p.m.2.5 filter samples were collected from five hospitals (i.e., oral, dermatology, chest, eye, and general hospitals) in Shandong Province, East China. The diversity of bacteria and fungi was analyzed at the species level using single-molecule real-time sequencing of the 16 S and internal transcribed spacer 1 (ITS) ribosomal genes, respectively. Significant differences were detected across sampling sites in terms of microbial diversity and community composition in PM2.5 as well as pollution concentrations. The range of PM2.5 concentrations observed in hospital halls was higher, ranging from 39.0 to 46.2 μg/m3, compared to the wards where the concentrations ranged from 10.7 to 25.2 μg/m3. Furthermore, microbial variations in PM2.5 bioaerosols were associated with hospital type. The most dominant pathogens identified were Vibrio metschnikovii, Staphylococcus epidermidis, Staphylococcus haemolyticus, Fusarium pseudensiforme, and Aspergillus ruber. Among these, A. ruber was identified as an opportunistic fungus in a hospital setting for the first time. Nine potentially novel strains of F. pseudensiforme, showing 84.5%-92.0% ITS sequence similarity to known Fusarium isolates, were identified in PM2.5 samples from all hospitals (excluding an eye hospital). This study highlights the importance of hospital environments in shaping microbial aerosol communities. To the best of our knowledge, this is the first study to provide insights into the bacterial and fungal biodiversity of PM2.5 in specialized hospitals, enriching research in healthcare environmental microbiology and carrying significant public health implications.

Screening, molecular identification, population diversity, and antibiotic susceptibility pattern of Actinomycetes species isolated from meat and meat products of slaughterhouses, restaurants, and meat stores of a developing country, Iran

Introduction

Actinomycetes can colonize surfaces of tools and equipment and can be transferred to meat and meat products during manufacture, processing, handling, and storage. Moreover, washing the meat does not eliminate the microorganisms; it only spreads them. As a result, these opportunistic pathogens can enter the human body and cause various infections. Therefore, the aim of the current study was to screen, identify, and determine the antibiotic susceptibility of Actinomycetes species from meat and meat products in the Markazi province of Iran.

Methods

A total of 60 meat and meat product samples, including minced meat, mutton, beef, chicken, hamburgers, and sausages, were collected from slaughterhouses, butchers, and restaurants in the Markazi province of Iran. The samples were analyzed using standard microbiological protocols for the isolation and characterization of Actinomycetes. PCR amplification of hsp65 and 16SrRNA genes and sequence analysis of 16SrRNA were used for genus and species identification. The minimum inhibitory concentrations (MICs) of antimicrobial agents were determined by the broth microdilution method and interpreted according to the CLSI guidelines.

Results

A total of 21 (35%) Actinomycetes isolates from 5 genera and 12 species were isolated from 60 samples. The most prevalent Actinomycetes were from the genus Mycobacterium, with six (28.6%) isolates (M. avium complex, M. terrae, M. smegmatis, and M. novocastrense), followed by the genus Rhodococcus with five (23.8%) isolates (R. equi and R. erythropolis), the genus Actinomyces with four (19.1%) isolates (A. ruminicola and A. viscosus), the genus Nocardia with four (19.1%) isolates (N. asiatica, N. seriolae, and N. niigatensis), and the genus Streptomyces with two (9.5%) isolates (S. albus). Chicken and sausage samples had the highest and lowest levels of contamination, with six and one isolates. Respectively, the results of drug susceptibility testing (DST) showed that all isolates were susceptible to Ofloxacin, Amikacin, Ciprofloxacin, and Levofloxacin, whereas all of them were resistant to Doxycycline and Rifampicin.

Discussion

The findings suggest that meat and meat products play an important role as a reservoir for the transmission of Actinomycetes to humans, thus causing life-threatening foodborne diseases such as gastrointestinal and cutaneous disorders. Therefore, it is essential to incorporate basic hygiene measures into the cycle of meat production to ensure food safety.

Dual Infection of an Open Fracture Caused by Mycobacterium setense and Clostridium celerecrescens

Infections caused by Mycobacterium setense or Clostridium celerecrescens are extremely rare. In this report, for the first time a dual infection with these two pathogens is described. An 18-year-old female suffered multiple injuries, including an open comminuted fracture of the right humeral diaphysis after falling from a fifth-floor balcony in January 2019. Five months after the accident, a fistula appeared in the scar, reaching the bone tissue. M. setense and C. celerecrescens were cultured from sinus swabs and subsequently from perioperative samples. The patient was initially treated with a combination of intravenous antibiotics (ATBs): imipenem, amikacin, and ciprofloxacin. One month after the fracture fixation with a titanium nail, C. celerecrescens was again detected; therefore, metronidazole was added to the therapy. A triple combination of oral (PO) ATBs (trimethoprim–sulfamethoxazole, moxifloxacin, and metronidazole) followed, 8 weeks after the initial intravenous therapy. C. celerecrescens was cultured again two times, most recently in November 2019, when surgical debridement was supplemented by the topical administration of cancellous bone impregnated with vancomycin. Signs of bone healing were found at follow-ups and ATB treatment was finished in March 2020 after a total of 9 months of therapy. To this day, there have been no signs of reinfection. This case thus illustrates the need for a combination of systemic and individualized local therapy in the treatment of complicated cases of dual infections with rare pathogens.