Microbiological Analysis of Hemodialysis Water in a Developing Country

Microbiological control of hemodialysis fluid is important for the prevention of hemodialysis-associated illness. Bacterial populations inhabiting a distribution system for hemodialysis water were studied over a 4 month period in five hospitals (one in Tehran, and the others at Alborz). All the samples from the four hospitals at Alborz had colony counts of ≥100 CFU/ml, which at different points of sampling were higher than the maximum recommended values. A total of 80 samples taken at different points in each hospital's hemodialysis distribution system were collected, and 229 planktonic bacteria isolated on R2A medium. No growth was detected by culturing the samples on Blood agar or Mueller-Hinton agar, according to routine procedures currently used in the five hospitals. A representative of isolates from each of 45 different morphotypes were identified using 16S RNA sequencing. A diverse bacterial community, containing predominantly gram-positive members of Kocuria, Arthrobacter and Staphylococcus and Mycobacterium, was detected. Bacteria from the genera Acinetobacter, Burkholderia, Halomonas, Herbaspirillum, Pseudomonas, and Sphingomonas were identified, which has been described in the build-up of biofilms. Some of the species reported here may represent a health risk to patients receiving hemodialysis treatment. In conclusion, it is recommended that standard protocols for evaluation of microbial contamination be used for regular monitoring and identification of culturable bacteria

In Vitro Antimicrobial Susceptibility of Nontuberculous Mycobacteria in Iran

Many species of nontuberculous mycobacteria (NTM) have long been identified as important causes of human disease, the incidence of which is rising. Several reports have suggested increasing trend of both in vitro and in vivo resistance to available treatment regimes. The aim of this study was to evaluate antibiotic susceptibility of clinically relevant NTM isolates using standard microbroth dilution test. Antimicrobial susceptibility testing was performed following National Committee for Clinical Laboratory Standards methods for NTM isolates, including 85 Mycobacterium fortuitum , 39 Mycobacterium chelonae , and 30 Mycobacterium abscessus subsp. abscessus as rapidly growing mycobacteria and 48 Mycobacterium simiae and 40 Mycobacterium kansasii as slowly growing mycobacteria. All isolates were recovered from various types of clinical samples and identified by multilocus sequence analysis. Trimethoprim–sulfamethoxazole (TMP-SMZ), amikacin, tobramycin, clarithromycin, moxifloxacin, linezolid, and imipenem showed better activity against M. fortuitum rather than meropenem, ciprofloxacin, cefoxitin, and doxycycline. Amikacin was active against 93% of M. abscessus subsp. abscessus. Linezolid, clarithromycin, cefoxitin, ciprofloxacin, imipenem, moxifloxacin, tobramycin, TMP-SMZ, doxycycline, and meropenem showed some activities on M. abscessus subsp. abscessus as well. The majority of M. abscessus subsp. abscessus and M. chelonae strains were multidrug resistant. Among the 40 isolates of M. kansasii , all were susceptible to ethambutol, isoniazid, clarithromycin, moxifloxacin, and linezolid. These isolates were also resistant to doxycycline and 50% were resistant to rifampicin and ciprofloxacin. M. simiae was resistant to clarithromycin, doxycycline, isoniazid, and TMP-SMZ, and the majority of isolates showed high levels of resistance to linezolid, ethambutol, ciprofloxacin, streptomycin, and rifampicin. The majority of M. simiae isolates were multidrug resistant. Our data confirm the need for performing of standard susceptibility testing of any clinically important NTM isolate

Mycobacterium ahvazicum sp. nov., the nineteenth species of the Mycobacterium simiae complex

Abstract Four slowly growing mycobacteria isolates were isolated from the respiratory tract and soft tissue biopsies collected in four unrelated patients in Iran. Conventional phenotypic tests indicated that these four isolates were identical to Mycobacterium lentiflavum while 16S rRNA gene sequencing yielded a unique sequence separated from that of M. lentiflavum. One representative strain AFP-003T was characterized as comprising a 6,121,237-bp chromosome (66.24% guanosine-cytosine content) encoding for 5,758 protein-coding genes, 50 tRNA and one complete rRNA operon. A total of 2,876 proteins were found to be associated with the mobilome, including 195 phage proteins. A total of 1,235 proteins were found to be associated with virulence and 96 with toxin/antitoxin systems. The genome of AFP-003T has the genetic potential to produce secondary metabolites, with 39 genes found to be associated with polyketide synthases and non-ribosomal peptide syntases and 11 genes encoding for bacteriocins. Two regions encoding putative prophages and three OriC regions separated by the dnaA gene were predicted. Strain AFP-003T genome exhibits 86% average nucleotide identity with Mycobacterium genavense genome. Genetic and genomic data indicate that strain AFP-003T is representative of a novel Mycobacterium species that we named Mycobacterium ahvazicum, the nineteenth species of the expanding Mycobacterium simiae complex