Chromosomal resistance to antibiotics in gonococci from Bahrain

Ninety-one isolates of non-penicillinase-producing Neisseria gonorrhoeae from patients in Bahrain were tested for serotype, auxotype, and antibiotic susceptibility. Ten serovars and three auxotypes were found. Of the 91 isolates, 49 (54%) were serovar IB-5/7, 59 (65%) had a penicillin MIC greater than or equal to 1 mg/l, 39 (45%) had a cefuroxime MIC greater than or equal to 0.5 mg/l, and 63 (69%) had a tetracycline MIC of greater than or equal to 4 mg/l. No spectinomycin or high-level tetracycline resistance was seen. Seventy of the 91 isolates were tested against ciprofloxacin and ceftriaxone, and 40 (57%) and 26 (37%) had MICs greater than or equal to 0.03 mg/l, respectively. DNA from two penicillin-resistant isolates was capable of transforming recipient strain FA19 to donor level of penicillin and cephalosporin resistance in four steps. The first three steps were indicative of the acquisition of known resistance mutations. The existence of the fourth level transformants, with the ability of donor DNA to transform strain FA140 to higher levels of resistance, suggest the presence of another resistance mutation.